Positioning System

ABSTRACT

System for determining accurate position of an object such as a vehicle includes a GPS positioning system arranged to communicate with one or more satellites to obtain GPS signals therefrom, a correction unit coupled to the positioning system and arranged to receive or derive positional corrections for positional data derived from the GPS signals to thereby improve accuracy of the position of the object provided by the positioning system, and a notification system for notifying a person concerned with the position of the object about the current position of the object. The correction unit may be a DGPS-based correction unit arranged to communicate with satellites to receive positional corrections therefrom and/or communicate with ground base stations to receive positional corrections therefrom.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is:

1. a continuation-in-part (CIP) of U.S. patent application Ser. No.11/304,502 filed Dec. 15, 2005, now U.S. Pat. No. 7,324,039, whichclaims priority under 35 U.S.C. § 119(e) of U.S. provisional patentapplication Ser. No. 60/636,574 filed Dec. 6, 2005, now expired; and

2. a CIP of U.S. patent application Ser. No. 11/461,619 filed Aug. 1,2006 which claims priority under 35 U.S.C. § 119(e) of U.S. provisionalpatent application Ser. No. 60/711,452 filed Aug. 25, 2005, now expired,and is:

-   -   A) a CIP of U.S. patent application Ser. No. 10/822,445 filed        Apr. 12, 2004, now U.S. Pat. No. 7,085,637, which is:        -   1) a CIP of U.S. patent application Ser. No. 10/118,858            filed Apr. 9, 2002, now U.S. Pat. No. 6,720,920, which is:            -   a) a CIP of U.S. patent application Ser. No. 09/177,041                filed Oct. 22, 1998, now U.S. Pat. No. 6,370,475, which                claims priority under 35 U.S.C. § 119(e) of U.S.                provisional patent application Ser. No. 60/062,729 filed                Oct. 22, 1997, now expired; and            -   b) a CIP of U.S. patent application Ser. No. 09/679,317                filed Oct. 4, 2000, now U.S. Pat. No. 6,405,132, which                is a CIP of U.S. patent application Ser. No. 09/523,559                filed Mar. 10, 2000, now abandoned, which claims                priority under 35 U.S.C. § 119(e) of U.S. provisional                patent application Ser. No. 60/123,882 filed Mar. 11,                1999, now expired; and            -   c) a CIP of U.S. patent application Ser. No. 09/909,466                filed Jul. 19, 2001, now U.S. Pat. No. 6,526,352; and        -   2) a CIP of U.S. patent application Ser. No. 10/216,633            filed Aug. 9, 2002, now U.S. Pat. No. 6,768,944; and    -   B) a CIP of U.S. patent application Ser. No. 11/028,386 filed        Jan. 3, 2005, now U.S. Pat. No. 7,110,880 which is a CIP of U.S.        patent application Ser. No. 10/822,445 filed Apr. 12, 2004, now        U.S. Pat. No. 7,085,637, the history of which is set forth        above; and    -   C) a CIP of U.S. patent application Ser. No. 11/034,325 filed        Jan. 12, 2005, now U.S. Pat. No. 7,202,776 which is a CIP of        U.S. patent application Ser. No. 10/822,445 filed Apr. 12, 2004,        now U.S. Pat. No. 7,085,637, the history of which is set forth        above;

3. a CIP of U.S. patent application Ser. No. 11/464,385 filed Aug. 14,2006 which claims priority under 35 U.S.C. § 119(e) of U.S. provisionalpatent application Ser. No. 60/711,452 filed Aug. 25, 2005, now expired,and is a CIP of U.S. patent application Ser. No. 11/028,386 filed Jan.3, 2005, now U.S. Pat. No. 7,110,880, and a CIP of U.S. patentapplication Ser. No. 11/034,325 filed Jan. 12, 2005, now U.S. Pat. No.7,202,776;

4. a CIP of U.S. patent application Ser. No. 11/562,730 filed Nov. 22,2006 which is a CIP of U.S. patent application Ser. No. 11/034,325 filedJan. 12, 2005, now U.S. Pat. No. 7,202,776, the history of which is setforth above;

5. a CIP of U.S. patent application Ser. No. 11/681,817 filed Mar. 5,2007 which is a CIP of U.S. patent application Ser. No. 11/034,325 filedJan. 12, 2005, now U.S. Pat. No. 7,202,776, the history of which is setforth above; and

6. a CIP of U.S. patent application Ser. No. 11/778,127 filed Jul. 16,2007.

This application is related to U.S. patent application Ser. No.11/874,418 filed Oct. 18, 2007, Ser. No. 11/874,732 filed Oct. 18, 2007and Ser. No. 11/874,749 filed Oct. 18, 2007 on the grounds that theyinclude common subject matter.

All of the above applications are incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to a positioning system forobjects such as vehicles. The positioning system can also be used forcell phones and emergency locator devices.

BACKGROUND OF THE INVENTION

A detailed discussion of background information is set forth in parentapplications, for example, U.S. patent application Ser. Nos. 09/679,317,10/822,445, 11/028,386 and 11/034,325, all of which are incorporated byreference herein.

All of the patents, patent applications, technical papers and otherreferences mentioned below and in the parent applications areincorporated by reference herein in their entirety. No admission is madethat any or all of these references are prior art and indeed, it iscontemplated that they may not be available as prior art wheninterpreting 35 U.S.C. § 102 in consideration of the claims of thepresent application.

Definitions of terms used in the specification and claims are also foundin the parent applications.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new and improvedpositioning system for objects such as vehicles.

In order to achieve this object and others, a system for determiningaccurate position of an object in accordance with the invention includesa GPS positioning system arranged to communicate with one or moresatellites to obtain GPS signals therefrom, a correction unit coupled tothe positioning system and arranged to receive or derive positionalcorrections for positional data derived from the GPS signals to therebyimprove accuracy of the position of the object provided by thepositioning system, and a notification system for notifying a personconcerned with the position of the object about the current position ofthe object. The object may be a vehicle, cell phone, emergency locatordevice and the like.

The correction unit may be a DGPS-based correction unit. The correctionunit may be arranged to communicate with satellites to receivepositional corrections therefrom and/or communicate with ground basestations to receive positional corrections therefrom.

A navigation system may be coupled to the correction unit for receivingand acting upon the accurate positional information of the objectprovided by the correction unit. When the object is a vehicle, a mapdatabase may be coupled to the navigation system which could thenreceive information about a travel lane the vehicle is traveling on andguide an operator of the vehicle based on the accurate positionalinformation and travel lane information. Autonomous guidance of avehicle is also envisioned. The notification system may thus be awarning system arranged to notify an operator of the vehicle of theposition of the vehicle to prevent accidents involving the vehicle. Adisplay may be provided for displaying the position of the vehicle on amap along with the position of other vehicles.

When the object is a vehicle, a system for communicating with othervehicles and transmitting GPS signals and/or positional corrections tothe other vehicles and/or receiving GPS signals and/or positionalcorrections from the other vehicles may be provided on the vehicle. Adisplay would be visible to the driver to display the position of thevehicle and other vehicles on a map.

In this regard, a vehicular system for determining accurate position ofthe vehicle in accordance with the invention includes a GPS positioningsystem arranged to communicate with one or more satellites to obtain GPSsignals therefrom, a correction unit coupled to the positioning systemand arranged to receive or derive positional corrections for positionaldata derived from the GPS signals to thereby improve accuracy of theposition of the vehicle provided by the positioning system, a system forcommunicating with other vehicles and transmitting GPS signals and/orpositional corrections to the other vehicles and/or receiving GPSsignals and/or positional corrections from the other vehicles, and adisplay for displaying the position of the vehicle and other vehicles ona map. Optionally, a notification or warning system is arranged on thevehicle for notifying an operator of the vehicle about a possiblecollision between the vehicle and one of the other vehicles. Theenhancements to the system described above are applicable here as well.

Other improvements will now be obvious to those skilled in the art. Theabove features are meant to be illustrative and not definitive.

Preferred embodiments of the inventions are shown in the drawings anddescribed in the detailed description below. Unless specifically noted,it is applicant's intention that the words and phrases in thespecification and claims be given the ordinary and accustomed meaning tothose of ordinary skill in the applicable art(s). If applicant intendsany other meaning, he will specifically state he is applying a specialmeaning to a word or phrase. In this regard, the words velocity andacceleration will be taken to be vectors unless stated otherwise. Speed,on the other hand, will be treated as a scalar. Thus, velocity willimply both speed and direction.

Likewise, applicant's use of the word “function” in the detaileddescription is not intended to indicate that he seeks to invoke thespecial provisions of 35 U.S.C. § 112, ¶6 to define his inventions. Tothe contrary, if applicant wishes to invoke the provision of 35 U.S.C. §112, ¶6, to define his inventions, he will specifically set forth in theclaims the phrases “means for” or “step for” and a function, withoutalso reciting in that phrase any structure, material or act in supportof the function. Moreover, even if applicant invokes the provisions of35 U.S.C. §112, ¶6, to define his inventions, it is applicant'sintention that his inventions not be limited to the specific structure,material or acts that are described in preferred embodiments. Rather, ifapplicant claims his inventions by specifically invoking the provisionsof 35 U.S.C. § 112, ¶6, it is nonetheless his intention to cover andinclude any and all structures, materials or acts that perform theclaimed function, along with any and all known or later developedequivalent structures, materials or acts for performing the claimedfunction.

For example, the present inventions make use of GPS satellite locationtechnology, including the use of MIR or RFID triads or radar andreflectors, to derive kinematic vehicle location and motion trajectoryparameters for use in a vehicle collision avoidance system and method.The inventions described herein are not to be limited to the specificGPS devices or PPS devices disclosed in the preferred embodiments, butrather, are intended to be used with any and all such applicablesatellite and infrastructure location devices, systems and methods, aslong as such devices, systems and methods generate input signals thatcan be analyzed by a computer to accurately quantify vehicle locationand kinematic motion parameters in real time. Thus, the GPS and PPSdevices and methods shown and referenced generally throughout thisdisclosure, unless specifically noted, are intended to represent any andall devices appropriate to determine such location and kinematic motionparameters.

Further, there are disclosed several processors or controllers, thatperform various control operations. The specific form of processor isnot important to the invention. In a preferred form, the computing andanalysis operations are divided into several cooperating computers ormicroprocessors. However, with appropriate programming well known tothose of ordinary skill in the art, the inventions can be implementedusing a single, high power computer. Thus, it is not applicant'sintention to limit his invention to any particular form or location ofprocessor or computer. For example, it is contemplated that in somecases, the processor may reside on a network connected to the vehiclesuch as one connected to the Internet.

Further examples exist throughout the disclosure, and it is notapplicant's intention to exclude from the scope of his inventions theuse of structures, materials, or acts that are not expressly identifiedin the specification, but nonetheless are capable of performing aclaimed function.

The above and other objects and advantages of the present invention areachieved by preferred embodiments that are summarized and describedbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The various hardware and software elements used to carry out theinvention described herein are illustrated in the form of systemdiagrams, block diagrams, flow charts, and depictions of neural networkalgorithms and structures. Preferred embodiments are illustrated in thefollowing figures:

FIG. 1 illustrates the GPS satellite system with the 24 satellitesrevolving around the earth.

FIG. 2 illustrates four GPS satellites transmitting position informationto a vehicle and to a base station which in turn transmits thedifferential correction signal to the vehicle.

FIG. 3 illustrates a WADGPS system with four GPS satellites transmittingposition information to a vehicle and to a base station which in turntransmits the differential correction signal to the vehicle.

FIG. 4 is a logic diagram showing the combination of the GPS system andan inertial navigation system.

FIG. 5 is a block diagram of the overall vehicle accident avoidance,warning, and control system and method of the present inventionillustrating system sensors, radio transceivers, computers, displays,input/output devices and other key elements.

FIG. 5A is a block diagram of a representative accident avoidance,warning and control system.

FIG. 6 is a block diagram of an image analysis computer of the type thatcan be used in the accident avoidance system and method of thisinvention.

FIG. 7 illustrates a vehicle traveling on a roadway in a definedcorridor.

FIG. 8 illustrates two adjacent vehicles traveling on a roadway andcommunicating with each other.

FIG. 9 is a schematic diagram illustrating a neural network of the typeuseful in the image analysis computer of FIG. 5.

FIG. 10 is a schematic diagram illustrating the structure of a nodeprocessing element in the neural network of FIG. 9.

FIG. 11 illustrates the use of a Precise Positioning System employingthree micropower impulse radar transmitters, two or three radarreflectors or three RFID tags in a configuration to allow a vehicle toaccurately determine its position.

FIG. 12 a is a flow chart of the method in accordance with the inventionfor preventing run off the road accidents.

FIG. 12 b is a flow chart of the method in accordance with the inventionfor preventing center (yellow) line crossing accidents.

FIG. 12 c is a flow chart of the method in accordance with the inventionfor preventing stoplight running accidents.

FIG. 13 illustrates an intersection with stop signs on the lesser roadwhere there is a potential for a front to side impact and a rear endimpact.

FIG. 14 illustrates a blind intersection with stoplights where there isa potential for a front side to front side impact.

FIG. 15 illustrates an intersection where there is a potential for afront-to-front impact as a vehicle turns into oncoming traffic.

FIG. 16A is a side view of a vehicle equipped with a road-mappingarrangement in accordance with the invention.

FIG. 16B is a front perspective view of a vehicle equipped with theroad-mapping arrangement in accordance with the invention.

FIG. 17 is a schematic perspective view of a data acquisition module inaccordance with the invention.

FIG. 17A is a schematic view of the data acquisition module inaccordance with the invention.

FIG. 18 shows the view of a road from the video cameras in both of thedata acquisition modules.

FIG. 19 shows a variety of roads and vehicles operating on those roadsthat are in communication with a vehicle that is passing through aPrecise Positioning Station.

FIG. 20 is a schematic of the manner in which communications between avehicle and a transmitter are conducted according to some embodiments ofthe invention.

FIGS. 21A and 21B illustrate a preferred embodiment of a laser radarsystem mounted at the four corners of a vehicle above the headlights andtail lights.

FIGS. 22A and 22B illustrate the system of FIGS. 21A and 21B forvehicles on a roadway.

FIGS. 23A and 23B illustrate an alternative mounting location for laserradar units.

FIG. 24 is a schematic illustration of a typical laser radar deviceshowing the scanning or pointing system with simplified optics.

FIG. 25 is a schematic showing a method for avoiding collisions inaccordance with the invention.

FIG. 26 is a schematic of a multi-form communication system inaccordance with the invention.

FIG. 27 is a schematic of a ubiquitous communication system inaccordance with the invention.

FIG. 28 shows a block diagram of the 76-77 GHz FMCW radar transceiverwith two antennas according to the hybrid integrated-waveguide preferredembodiment.

FIG. 29 shows the circuit for matching the multiplier IMPATT diode ofFIG. 28 both with waveguide and microstrip transmission lines accordingto the hybrid integrated-waveguide preferred embodiment.

FIG. 30 shows schematically cross-section of a packaged Si multiplierIMPATT diode optimized for the 76-77 GHz range according to the hybridintegrated-waveguide preferred embodiment.

FIG. 31 shows a block diagram of the 76-77 GHz FMCW radar transceiverwith one antenna according to the hybrid integrated-microstripembodiment of the invention.

FIG. 32 shows a block diagram of the 76-77 GHz active silicon IMPATTfrequency multiplier according to the hybrid integrated-microstripembodiment of the invention.

FIG. 33 shows the layout of the MM-wave section of the 76-77 GHz FMCWradar transceiver according to the hybrid integrated-microstripembodiment of the invention.

FIG. 34 is a schematic of a vehicle showing transceivers used forcollision avoidance in accordance with the invention.

FIG. 35 is a schematic of a vehicle showing transceivers used for blindspot monitoring in accordance with the invention.

DETAILED DISCUSSION OF PREFERRED EMBODIMENTS 1. Vehicle CollisionWarning and Control

According to U.S. Pat. No. 5,506,584, the stated goals of the US DOTIVHS system are:

-   -   improving the safety of surface transportation    -   increasing the capacity and operational efficiency of the        surface transportation system    -   enhancing personal mobility and the convenience and comfort of        the surface transportation system    -   reducing the environmental and energy impacts of the surface        transportation system

The RtZF® system in accordance with the present invention satisfies allof these goals at a small fraction of the cost of prior art systems. Thesafety benefits have been discussed above. The capacity increase isachieved by confining vehicles to corridors where they are thenpermitted to travel at higher speeds. This can be achieved immediatelywhere carrier phase DGPS is available or with the implementation of thehighway-located precise location systems as shown in FIG. 11. Animprovement is to add the capability for the speed of the vehicles to beset by the highway or highway control system. This is a simpleadditional few bytes of information that can be transmitted along withthe road edge location map, thus, at very little initial cost. Toaccount for the tolerances in vehicle speed control systems, thescanning laser radar, or other technology system, which monitors for thepresence of vehicles without RtZF® is also usable as an adaptive cruisecontrol system. Thus, if a faster moving vehicle approaches a slowermoving vehicle, it will automatically slow down to keep a safeseparation distance from the leading, slower moving vehicle. Althoughthe system is not planned for platooning, that will be the automaticresult in some cases. The maximum packing of vehicles is automaticallyobtained and thus the maximum vehicle flow rate is also achieved with avery simple system.

For the Intelligent Highway System (ITS) application, some provision isrequired to prevent unequipped vehicles from entering the restrictedlanes. In most cases, a barrier will be required since if an errantvehicle did enter the controlled lane, a serious accident could result.Vehicles would be checked while traveling down the road or at atollbooth, or similar station, that the RtZF® system was in operationwithout faults and with the latest updated map for the region. Onlythose vehicles with the RtZF® system in good working order would bepermitted to enter. The speed on the restricted lanes would be setaccording to the weather conditions and fed to the vehicle informationsystem automatically, as discussed above. Automatic tolling based on thetime of day or percentage of highway lane capacity in use can also beeasily implemented.

For ITS use, there needs to be a provision whereby a driver can signalan emergency, for example, by putting on the hazard lights. This wouldpermit the vehicle to leave the roadway and enter the shoulder when thevehicle speed is below a certain level. Once the driver provides such asignal, the roadway information system, or the network of vehicle-basedcontrol systems, would then reduce the speed of all vehicles in thevicinity until the emergency has passed. This roadway information systemneed not be actually associated with the particular roadway and alsoneed not require any roadway infrastructure. It is a term used here torepresent the collective system as operated by the network of nearbyvehicles and the inter-vehicle communication system. Eventually, theoccurrence of such emergency situations will be eliminated byvehicle-based failure prediction systems such as described in U.S. Pat.No. 5,809,437.

Emergency situations will develop on intelligent highways. It isdifficult to access the frequency or the results of such emergencies.The industry has learned from airbags that if a system is developedwhich saves many lives but causes a few deaths, the deaths will not betolerated. The ITS system, therefore, must operate with a very highreliability, that is approaching “zero fatalities”™. Since the brains ofthe system will reside in each vehicle, which is under the control ofindividual owners, there will be malfunctions and the system must beable to adapt without causing accidents. An alternative is for thebrains to reside on the network providing that the network connection isreliable.

Spacing of the vehicles is the first line of defense. Secondly, eachvehicle with a RtZF® system has the ability to automatically communicateto all adjacent vehicles and thus immediately issue a warning when anemergency event is occurring. Finally, with the addition of a totalvehicle diagnostic system, such as disclosed in U.S. Pat. No. 5,809,437,potential emergencies can be anticipated and thus eliminated with highreliability.

Although the application for ITS envisions a special highway lane andhigh speed travel, the potential exists in the invention to provide alower measure of automatic guidance where the operator can turn controlof the vehicle over to the RtZF® system for as long as theinfrastructure is available. In this case, the vehicle would operate innormal lanes but would retain its position in the lane and avoidcollisions until a decision requiring operator assistance is required.At that time, the operator would be notified and if he or she did notassume control of the vehicle, an orderly stopping of the vehicle, e.g.,on the side of the road, would occur.

For all cases where vehicle steering control is assumed by the RtZF®system, an algorithm for controlling the steering should be developedusing neural networks or neural fuzzy systems. This is especially truefor the emergency cases discussed herein where it is well known thatoperators frequently take the wrong actions and at the least, they areslow to react. Algorithms developed by other non-pattern recognitiontechniques do not, in general, have the requisite generality orcomplexity and are also likely to make the wrong decisions (although theuse of such systems is not precluded in the invention). When thethrottle and breaking functions are also handled by the system, analgorithm based on neural networks or neural fuzzy systems is even moreimportant.

For the ITS, the driver will enter his or her destination so that thevehicle knows ahead of time where to exit. Alternately, if the driverwishes to exit, he merely turns on his turn signal, which tells thesystem and other vehicles that he or she is about to exit the controlledlane.

Neural networks have been mentioned above and since they can play animportant role in various aspects of the invention, a brief discussionis now presented here. FIG. 9 is a schematic diagram illustrating aneural network of the type useful in image analysis. Data representingfeatures from the images from the CMOS cameras 60 are input to theneural network circuit 63, and the neural network circuit 63 is thentrained on this data (see FIG. 6). More specifically, the neural networkcircuit 63 adds up the feature data from the CMOS cameras 60 with eachdata point multiplied by an associated weight according to theconventional neural network process to determine the correlationfunction.

In this embodiment, 141 data points are appropriately interconnected at25 connecting points of layer 1, and each data point is mutuallycorrelated through the neural network training and weight determinationprocess. In some implementations, each of the connecting points of thelayer 1 has an appropriate threshold value, and if the sum of measureddata exceeds the threshold value, each of the connecting points willoutput a signal to the connecting points of layer 2. In other cases, anoutput value or signal will always be outputted to layer 2 withoutthresholding.

The connecting points of the layer 2 comprises 20 points, and the 25connecting points of the layer 1 are appropriately interconnected as theconnecting points of the layer 2. Similarly, each data value is mutuallycorrelated through the training process and weight determination asdescribed above and in neural network texts. Each of the 20 connectingpoints of the layer 2 can also have an appropriate threshold value, ifthresholding is used, and if the sum of measured data exceeds thethreshold value, each of the connecting points will output a signal tothe connecting points of layer 3.

The connecting points of the layer 3 comprises 3 points in this example,and the connecting points of the layer 2 are interconnected at theconnecting points of the layer 3 so that each data is mutuallycorrelated as described above.

The value of each connecting point is determined by multiplying weightcoefficients and summing up the results in sequence, and theaforementioned training process is to determine a weight coefficient Wjso that the value (ai) is a previously determined output.

ai=ΣWj·Xj(j=1 to N)+W ₀

wherein

-   -   Wj is the weight coefficient,    -   Xj is the data    -   N is the number of samples and    -   W₀ is bias weight associated with each node.

Based on this result of the training, the neural network circuit 63generates the weights and the bias weights for the coefficients of thecorrelation function or the algorithm.

At the time the neural network circuit 63 has learned from a suitablenumber of patterns of the training data, the result of the training istested by the test data. In the case where the rate of correct answersof the object identification unit based on this test data isunsatisfactory, the neural network circuit 63 is further trained and thetest is repeated. Typically, about 200,000 feature patterns are used totrain the neural network 63 and determine all of the weights. A similarnumber is then used for the validation of the developed network. In thissimple example chosen, only three outputs are illustrated. These canrepresent another vehicle, a truck and a pole or tree. This might besuitable for an early blind spot detector design. The number of outputsdepends on the number of classes of objects that are desired. However,too many outputs can result in an overly complex neural network and thenother techniques such as modular neural networks can be used to simplifythe process. When a human looks at a tree, for example, he or she mightthink “what kind of tree is that?” but not “what kind of tiger is that”.The human mind operates with modular or combination neural networkswhere the object to be identified is first determined to belong to ageneral class and then to a subclass etc. Object recognition neuralnetworks can frequently make use of this principle with a significantsimplification resulting.

In the above example, the image was first subjected to a featureextraction process and the feature data was input to the neural network.In other cases, especially as processing power continues to advance, theentire image is input to the neural network for processing. Thisgenerally requires a larger neural network. Alternate approaches usedata representing the difference between two frames and the input datato the neural network. This is especially useful when a moving object ofinterest is in an image containing stationary scenery that is of nointerest. This technique can be used even when everything is moving byusing the relative speed as a filter to remove unwanted pixel data. Anyvariations are possible and will now be obvious to those skilled in theart. Alternately, this image can be filtered based on range, which willalso significantly reduce the number of pixels to be analyzed.

In another implementation, the scenes are differenced based onillumination. If infrared illumination is used, for example, theillumination can be turned on and off and images taken and thendifferenced. If the illumination is known only to illuminate an objectof interest then such an object can be extracted from the background bythis technique. A particularly useful method is to turn the illuminationon and off for alternate scan lines in the image. Adjacent scan linescan then be differenced and the resulting image sent to the neuralnetwork system for identification.

The neural network can be implemented as an algorithm on ageneral-purpose microprocessor or on a dedicated parallel processingDSP, neural network ASIC or other dedicated parallel or serialprocessor. The processing speed is generally considerably faster whenparallel processors are used and this can also permit the input of theentire image for analysis rather than using feature data. A combinationof feature and pixel data can also be used.

Neural networks have certain known potential problem areas that variousresearchers have attempted to eliminate. For example, if datarepresenting an object that is totally different from those objectspresent in the training data is input to the neural network, anunexpected result can occur which, in some cases, can cause a systemfailure. To solve this and other neural network problems, researchershave resorted to adding in some other computational intelligenceprinciples such as fuzzy logic resulting in a neural-fuzzy system, forexample. As the RtZF® system evolves, such refinements will beimplemented to improve the accuracy of the system. Thus, although pureneural networks are currently being applied to the problem, hybridneural networks such as modular, combination, ensemble and fuzzy neuralnetworks will undoubtedly evolve.

A typical neural network processing element known to those skilled inthe art is shown in FIG. 10 where input vectors, (X1, X2, . . . , Xn)are connected via weighing elements 120 (W1, W2, . . . , Wn) to asumming node 130. The output of node 130 is passed through a nonlinearprocessing element 140, typically a sigmoid function, to produce anoutput signal, Y. Offset or bias inputs 125 can be added to the inputsthrough weighting circuit 128. The output signal from summing node 130is passed through the nonlinear element 140 which has the effect ofcompressing or limiting the magnitude of the output Y.

Neural networks used in the accident avoidance system of this inventionare trained to recognize roadway hazards including automobiles, trucks,animals and pedestrians. Training involves providing known inputs to thenetwork resulting in desired output responses. The weights areautomatically adjusted based on error signal measurements until thedesired outputs are generated. Various learning algorithms may beapplied with the back propagation algorithm with the Delta Bar rule as aparticularly successful method.

2. Accurate Navigation

2.1 GPS

FIG. 1 shows the current GPS satellite system associated with the earthand including 24 satellites 2, each satellite revolving in a specificorbital path 4 around the earth. By means of such a GPS satellitesystem, the position of any object can be determined with varyingdegrees of precision as discussed herein. A similar system will appearwhen the European Galileo system is launched perhaps doubling the numberof satellites.

2.2 DGPS, WAAS, LAAS and Pseudolites

FIG. 2 shows an arrangement of four satellites 2 designated SV₁, SV₂,SV₃ and SV₄ of the GPS satellite system shown in FIG. 1 transmittingposition information to receiver means of a base station 20, such as anantenna 22, which in turn transmits a differential correction signal viatransmitter means associated with that base station, such as a secondantenna 16, to a vehicle 18.

Additional details relating to FIGS. 1 and 2 can be found in U.S. Pat.No. 5,606,506.

FIG. 3 shows an arrangement of four satellites 2 designated SV₁, SV₂,SV₃ and SV₄ of the GPS satellite system as in FIG. 2 transmittingposition information to receivers of base stations 20 and 21, such as anantenna 22, which in turn transmit a differential correction signal viatransmitters associated with that base stations, such as a secondantenna 16, to a geocentric or low earth orbiting (LEO) satellite 30which in turn transmits the differential correction signals to vehicle18. In this case, one or more of the base stations 20,21 receives andperforms a mathematical analysis on all of the signals received from anumber of base stations that cover the area under consideration andforms a mathematical model of the errors in the GPS signals over theentire area. For the CONUS, for example, a group of 13 base stations areoperated by OmniStar that are distributed around the country. Byconsidering data from the entire group of such stations, the errors inthe GPS signals for the entire area can be estimated resulting in aposition accuracy of about 6-10 cm over the entire area. The correctionsare then uploaded to the geocentric or low earth orbiting satellite 30for retransmission to vehicles on the roadways. In this way, suchvehicles are able to determine their absolute position to within about6-10 centimeters. This is known as Wide Area Deferential GPS or WADGPS.The wide area corrections can be further corrected when there areadditional local stations that are not part of the WADGPS system.

It is important to note that future GPS and Galileo satellite systemsplan for the transmission of multiple frequencies for civilian use. Likea lens, the ionosphere diffracts different frequencies by differentamounts and thus the time of arrival of a particular frequency willdepend on the value of that frequency. This fact can be used todetermine the amount that each frequency is diffracted and thus thedelay or error introduced by the ionosphere. Thus with more than onefrequency being emitted by a particular satellite, the equivalent of theDGPS corrections can be determined be each receiver and there is nolonger a need for DGPS, WADGPS, WAAS, LAAS and similar systems.

The WAAS system is another example of WADGPS for use with airplanes. TheU.S. Government estimates that the accuracy of the WAAS system is about1 meter in three dimensions. Since the largest error is in the verticaldirection, the horizontal error is much less.

2.3 Carrier Phase Measurements

If a receiver can receive signals by two paths from a satellite it canmeasure the phase difference between the two paths and, provided thatthere are not any extra cycles in one of the paths, the path differencecan be determined to less than one centimeter. The fact that there maybe an integer number of extra cycles in one path and not in the other iswhat is called the integer ambiguity problem and a great deal ofattention has been paid in the literature to resolving this ambiguity.Using the Precise Positioning System (PPS) described below where avehicle becomes its own DGPS system, the carrier phase ambiguity problemalso disappears since the number of additional cycles can be determinedas the vehicle travels away from the PPS. In other words, there are noextra cycles when the vehicle is at the PPS and as it moves away, itwill still know the state of the cycles at the PPS and can thencalculate the increase or decrease in the cycles at the host vehicle asit moves relatively away from or closer to the transmitting satellite.There is no ambiguity when the vehicle is at the PPS station and that ismaintained as long as the lock on a satellite is not lost for more thana few minutes providing that there is an accurate clock within thevehicle.

There are other sources of information that can be added to increase theaccuracy of position determination. The use of GPS with four satellitesprovides the three dimensional location of the vehicle plus time. Of thedimensions, the vertical position is the least accurately known, yet, ifthe vehicle knows where it is on the roadway, the vertical dimension isnot only the least important but it is also already accurately knownfrom the roadmap information plus the inertial guidance system.

2.4 Inertial Navigation System

In the system of the inventions herein, the vehicle will generally havean inertial measurement unit, inertial reference unit or an inertialnavigation system which for the purposes herein will be treated asidentical. Such a device typically has three accelerometers and threegyroscopes that are held together in a single housing. Typically, these6 devices are MEMS devices and inherently are very inexpensive. Somecompanies then proceed to carefully test each component to determine therepeatable effects that various environmental factors and aging has onthe performance of each device, and then associates with each device acalibration or constitute equation that translates the readings of thedevice to actual values based on the environmental variable values andtime. This process adds significantly to the cost and in fact may be thedominant cost. The problem is that age, for example, may affect a devicedifferently based on how the aging takes place, at high or lowtemperatures, for example. Also shock or some other unexpected event canchange the properties of a device. In the present invention, on theother hand, this complicated and expensive calibration process is notperformed and thus a calibration equation is not frozen into the device.Since the IMU will be part of a vehicle system and that system willperiodically, either from the GPS-DGPS type system or from the PPS, knowits exact location, that fact will be used to derive a calibrationequation for each device and since other information such as temperatureetc. will also be known that parameter can also be part of the equation.The equation can thus be a changing part of the system thatautomatically adjusts to actual experience of the vehicle in the field.Thus, not only is the IMU more accurate than the prior art but it isconsiderably less expensive. One method for handling this change andrecalculation of the calibration equations would be to use an adaptiveneural network that has a forgetting function. Properly designed, thisnetwork can allow the calibration equations to adjust and slowly changeover time always providing the most accurate values regardless of howthe devices are changing in their sensitivity to temperature, forexample.

The fact that the IMU resident devices are continuously calibrated usingexternal measurements renders the IMU an extremely accurate devicecomparable with military grade IMUs costing thousands of dollars. TheIMU is far more accurate, for example, than the crash sensor or chassiscontrol accelerometers and gyroscopes that are currently being deployedon a vehicle. Thus, when mounting location considerations permit, theIMU can take over the functions currently performed by these otherdevices. This will not only increase the accuracy of these otherfunctions but reduce the total cost by eliminating the need forredundant parts and permitting economies in the electronic circuits andprocessors to be realized. The airbag SDM can now be housed with theIMU, for example, or the IMU can be housed within the SDM, and similarlyfor the chassis control electronics. If the IMU has the full complementof three gyros and three accelerometers, then this additionalinformation can be used to substantially improve the crash sensingalgorithms or the chassis control algorithms. The sensing and predictingor a rollover event, for example, and the subsequent control of thethrottle, brakes and steering systems as well as the timely deploymentof the side and curtain airbags. Thus, the use of the IMU for thesefunctions, particularly for the rollover prediction, mitigation andrestraint deployment functions, are a key teaching of this invention.

Airplanes, especially small private planes, have an assortment ofgyroscopes, accelerometers etc., but these sensors are not believed tohave been combined into a single MEMS-packaged IMU where corrections areaccomplished b an error correction determining system through requiringinternal consistency of the individual inertial devices and/or throughthe use of a Kalman Filter and/or DGPS. DGPS corrections are believed tobe available through the WAAS system to all airborne planes and the LAAScan be used for travel on and near airports. If not available, thenother location sources can be used including the broadcast of DGPScorrections or through communication with ground stations, or theinternet, the corrected coordinates can be sent to the plane. WAAS andLAAS were planned for aircraft but they were not intended for use toallow a cheap MEMS IMU (or a subset device having less than 3 gyros and3 accelerometers) to be used.

As discussed below, many sensors can be used to correct the errors inthe IMU in addition to the GPS and PPS-based systems, and thus could bepart of the error correction determining system. A gravity meter candetermine the direction of vertically down and can especially be usedwhen the vehicle is not moving. A magnetic flux gate compass and/ordeclinometer values can be included in the map database and compared bythe host vehicle as it passes mapped areas. Doppler radar or othervelocity measurements from the exterior vehicle monitoring system canprovide valuable velocity information. Vision systems can be used tocorrect for position if such data is stored on the map database. If, forexample, a stored picture shows a signpost at a particular location thatcan be viewed by a resident vision system, then this can also be usefulinformation for correcting errors in the IMU.

In many cases, especially before the system implementation becomesmature and the complete infrastructure is in place, there will be timeswhen a particular vehicle system is not operational. This could be dueto obstructions hiding a clear view of a sufficient number of GPSsatellites, such as when a vehicle enters a tunnel. It could also be dueto a lack of road boundary information, due to construction or the factthat the road has not been surveyed and the information recorded andmade available to the vehicle, or a variety of other causes. It iscontemplated, therefore, that each equipped vehicle will contain awarning light or other system that warns the driver or the vehiclecontrol system when the system is not operational. If this occurs on oneof the specially designated highway lanes, the vehicle speed will bereduced until the system again becomes operational.

When the system is non-operational for a short distance, the vehiclewill still accurately know its position if there is, in addition, one ormore laser gyroscopes, micromachined angular rate sensors or equivalent,and one or more accelerometers that together are referred to as anInertial Navigation System (INS, IMU) or inertial measurement unit(IMU). Generally, such an INS or IMU will have three gyroscopes andthree accelerometers (although different numbers of gyroscopes andaccelerometers may be used) and frequently there may be more than oneIMU in a vehicle. Although current versions of the IMU use MEMS devices,progress is being made on fiber optic-based gyroscopes. Thus, thepresent invention is not limited to MEMS devices but will make use ofthe best cost effective devices that are available at a particular time.

As more sensors which are capable of providing information on thevehicle position, velocity and acceleration are added onto the vehicle,the system can become sufficiently complicated as to require a Kalmanfilter, neural network, or neural-fuzzy, system to permit the optimumusage of the available information. This becomes even more importantwhen information from outside the vehicle other than the GPS relatedsystems becomes more available. For example, a vehicle may be able tocommunicate with other vehicles that have similar systems and learntheir estimated location. If the vehicle can independently measure theposition of the other vehicle, for example through the use of thescanning laser radar system described below, the differenced GPSreadings as discussed above, and thereby determine the relative positionof the two or more vehicles, a further improvement of the position canbe determined for all such vehicles. Adding all such additionalinformation into the system would probably require a computationalmethod such as Kalman filters, neural networks or a combination thereofand perhaps a fuzzy logic system.

One way to imagine the system operation is to consider each car androadway edge to behave as if it had a surrounding “force field” thatwould prevent it from crashing into another vehicle or an obstacle alongthe roadway. A vehicle operator would be prevented from causing his orher vehicle to leave its assigned corridor. This is accomplished with acontrol system that controls the steering, acceleration and perhaps thevehicle brakes based on its knowledge of the location of the vehicle,highway boundaries and other nearby vehicles. In a preferredimplementation, the location of the vehicle is determined by first usingthe GPS L1 signal to determine its location within approximately 100meters. Then, using DGPS and corrections which are broadcast, whether byFM or downloaded from geo-synchronous (GEO) or Low Earth Orbiting (LEO)satellites or obtained from another vehicle or road-based transmitters,to determine its location within less than about 10 centimeters.Finally, the use of a PPS, discussed below, periodically permits thevehicle to determine its exact location and thereby determine the GPScorrections, eliminate the carrier cycle ambiguity and correct theerrors in the INS or IMU system. If this is still not sufficient, thenthe phase of the carrier frequency provides the required locationinformation to less than a few centimeters. Dead reckoning, usingvehicle speed, steering angle and tire rotation information and inertialguidance, can be used to fill in the gaps. Where satellites are out ofview, pseudolites, or other systems, can be placed along the highway. Apulsed scanning infrared laser or terahertz radar system, or anequivalent system, can be used for obstacle detection. Communication toother vehicles is by short distance radio or by spread spectrum timedomain pulse radar or terahertz.

3. Maps and Mapping

3.1 Maps

All information regarding the road, both temporary and permanent, shouldbe part of the map database, including speed limits, presence of guardrails, width of each lane, width of the highway, width of the shoulder,character of the land beyond the roadway, existence of poles or treesand other roadside objects, exactly where the precise position locationapparatus is located, etc. The speed limit associated with particularlocations on the maps should be coded in such a way that the speed limitcan depend upon the time of day and the weather conditions. In otherwords, the speed limit is a variable that will change from time to timedepending on conditions. It is contemplated that there will be a displayfor various map information which will always be in view for thepassenger and for the driver at least when the vehicle is operatingunder automatic control. Additional user information can thus also bedisplayed such as traffic conditions, weather conditions,advertisements, locations of restaurants and gas stations, etc.

A map showing the location of road and lane boundaries can be easilygenerated using a specially equipped survey vehicle that has the mostaccurate position measurement system available. In some cases, it mightbe necessary to set up one or more temporary local DGPS base stations inorder to permit the survey vehicle to know its position within a fewcentimeters. The vehicle would drive down the roadway while operators,using specially designed equipment, sight the road edges and lanes. Thiswould probably best be done with laser pointers and cameras. Transducersassociated with the pointing apparatus record the angle of the apparatusand then by triangulation determine the distance of the road edge orlane marking from the survey vehicle. Since the vehicle's position wouldbe accurately known, the boundaries and lane markings can be accuratelydetermined. It is anticipated that the mapping activity would take placecontinuously such that all roads in a particular state would beperiodically remapped in order to record any changes which were missedby other monitoring systems and to improve the reliability of the mapsby minimizing the chance for human error. Any roadway changes that werediscovered would trigger an investigation as to why they were notrecorded earlier thus adding feedback to the mapping part of theprocess.

The above-described method depends on human skill and attention and thusis likely to result in many errors. A preferred approach is to carefullyphotograph the edge of the road and use the laser pointers to determinethe location of the road lines relative to the pointers and to determinethe slope of the roadway through triangulation. In this case, severallaser pointers would be used emanating from above, below and/or to thesides of the camera. The reduction of the data is then done later usingequipment that can automatically pick out the lane markings and thereflected spots from the laser pointers. One aid to the mapping processis to place chemicals in the line paint that could be identified by thecomputer software when the camera output is digitized. This may requirethe illumination of the area being photographed by an infrared orultraviolet light, for example.

In some cases where the roadway is straight, the survey vehicle couldtravel at moderate speed while obtaining the boundary and lane locationinformation. In other cases, where the road in turning rapidly, morereadings would be required per mile and the survey vehicle would need totravel more slowly. In any case, the required road information can beacquired semi-automatically with the survey vehicle traveling at amoderate speed. Thus, the mapping of a particular road would not requiresignificant time or resources. It is contemplated that a few such surveyvehicles could map all of the interstate highways in the U.S. in lessthan one year. Eventually, it is contemplated that between 50 and 100such vehicles using photogramity techniques would continuously map andremap the Unites States.

The mapping effort could be supplemented and cross-checked though theuse of accurate detailed digital photogrammetic systems which, forexample, can determine the road altitude with an accuracy to <50 cm.Efforts are underway to map the earth with 1-meter accuracy. Thegenerated maps could be used to check the accuracy and for missinginfrastructure or other roadside installations of the road-determinedmaps.

A preferred approach is to accomplish the majority of the mappingfunction utilizing a vehicle equipped with a selection of severalcameras, accurate RTK DGPS and appropriate illumination including one ormore laser pointers or equivalent. The resulting pictures wouldinitially be converted to maps manually but eventually, most of theprocess could be automated. Such map creation can be economicallyaccomplished by the Karpensky Institute in Kyiv, Ukraine. Thisinstitute, in combination with the inventors herein, have furtherdesigned a vehicle capable of collecting the required photographic data.

Another improvement that can be added to the system based on the maps isto use a heads-up display for in-vehicle signage. As the vehicle travelsdown the road, the contents of roadside signs can be displayed on aheads up display, providing such a display is available in the vehicle,or on a specially installed LCD display. This is based on the inclusionin the map database of the contents of all highway signs. A furtherimprovement would be to include signs having varying messages whichwould require that the message be transmitted by the sign to the vehicleand received and processed for in-vehicle display. This could be doneeither directly, by satellite, the Internet, cell phone etc.

As the roadway is being mapped, the availability of GPS satellite viewand the presence of multipath reflections from fixed structures can alsobe determined. This information can then be used to determine theadvisability of locating a local precise location system (PPS), or otherinfrastructure, at a particular spot on the roadway. Cars can also beused as probes for this process and for continuous improvement to checkthe validity of the maps and report any errors.

Multipath is the situation where more than one signal from a satellitecomes to a receiver with one of the signals resulting from a reflectionoff of a building or the ground, for example. Since multipath is afunction of geometry, the system can be designed to eliminate itseffects based on highway surveying and appropriate antenna design.Multipath from other vehicles can also be eliminated since the locationof the other vehicles will be known.

3.2 Mapping

An important part of some embodiments of the invention is the digitalmap that contains relevant information relating to the road on which thevehicle is traveling. The digital map usually includes the location ofthe edge of the road, the edge of the shoulder, the elevation andsurface shape of the road, the character of the land beyond the road,trees, poles, guard rails, signs, lane markers, speed limits, etc. asdiscussed elsewhere herein. Additionally, it can contain the signatureas discussed above. This data or information is acquired in a uniquemanner for use in the invention and the method for acquiring theinformation and its conversion to a map database that can be accessed bythe vehicle system is part of this invention. The acquisition of thedata for the maps will now be discussed. It must be appreciated thoughthat the method for acquiring the data and forming the digital map canalso be used in other inventions.

Local area differential GPS can be utilized to obtain maps with anaccuracy of about 2.0 cm (one sigma). Temporary local differentialstations are available from such companies as Trimble Navigation. Theselocal differential GPS stations can be placed at an appropriate spacingfor the road to be mapped, typically every 30 kilometers. Once a localdifferential GPS station is placed, it requires some time period such asan hour or more for the station to determine its precise location.Therefore, sufficient stations are required to cover the area that is tobe mapped within, for example, four hours. This may require as many as10 or more such differential stations for efficient mapping.

With reference to FIGS. 16A, 16B, 17 and 17A, a mapping vehicle 200 isused and obtains its location from GPS satellites and its correctionsfrom the local differential stations. Such a system is capable ofproviding the 2 cm accuracy desired for the map database. Typically, atleast two GPS receivers 226 are mounted on the mapping vehicle 200. EachGPS receiver 226 is contained within or arranged in connection with arespective data acquisition module 202, which data acquisition modules202 also contain a GPS antenna 204, an accurate inertial measurementunit (IMU) 206, a forward-looking video camera 208, a downward andoutward looking linear array camera 210 and a scanning laser radar 212.The relative position of these components in FIG. 17 is not intended tolimit the invention.

A processor including a printed circuit board 224 is coupled to the GPSreceivers 226, the IMUs 206, the video cameras 208, the linear cameras210 and the scanning laser radars 212 (see FIG. 17A). The processor 224receives information regarding the position of the vehicle from the GPSreceivers 226, and optionally the IMUs 206, and the information aboutthe road from both linear cameras 210 or from both laser radars 212, orfrom all of the linear cameras 210 and laser radars 212, and forms theroad map database. Information about the road can also come from one orboth of the video cameras 208 and be incorporated into the map database.

An alternate preferred approach uses a series of 4-6 cameras lookingforward, backward, and one, two or more on each side. In thisconfiguration, the linear cameras and scanning laser radars can beomitted and all relevant information comes from the IMU and GPS withdifferential corrections. The scene may be illuminated with generalillumination which can be in the IR part of the spectrum. In some cases,laser pointers or another form of structured light is also usedprimarily to permit later analysis of various elevation changes,especially at the side of the roadway. The resulting data is analyzedusing photogramity techniques to obtain a fully digital map.

The map database can be of any desired structure or architecture.Preferred examples of the database structure are of the type discussedin U.S. Pat. No. 6,144,338 (Davies) and U.S. Pat. No. 6,247,019(Davies).

The data acquisition modules 202 are essentially identical and each canmount to the vehicle roof on an extension assembly 214 which extendsforward of the front bumper. Extension assembly 214 can include amounting bracket 216 from the roof of the vehicle 200 forward to eachdata acquisition module 210, a mounting bracket 218 extending from thefront bumper upward to each data acquisition module 202 and a crossmounting bracket 220 extending between the data acquisition modules 202for support. Since all of the data acquisition equipment is co-located,its precise location is accurately determined by the IMU, the mountinglocation on the vehicle and the differential GPS system.

The forward-looking video cameras 208 can provide views of the road asshown in FIG. 18. These cameras 208 permit the database team to observethe general environment of the road and to highlight any anomalies. Theyalso permit the reading of traffic signs and other informationaldisplays all of which can be incorporated into the database. The cameras208 can be ordinary color video cameras, high-speed video cameras, wideangle or telescopic cameras, black and white video cameras, infraredcameras, etc. or combinations thereof. In some cases, special filtersare used to accentuate certain features. For example, it has been foundthat lane markers frequently are more readily observable at particularfrequencies, such as infrared. In such cases, filters can be used infront of the camera lens or elsewhere in the optical path to blockunwanted frequencies and pass desirable frequencies. Polarizing lenseshave also been found to be useful in many cases. Natural illuminationcan be used in the mapping process, but for some particular cases,particularly in tunnels, artificial illumination can also be used in theform of a floodlight or spotlight that can be at any appropriatefrequency of the ultraviolet, visual and infrared portions of theelectromagnetic spectrum or across many frequencies. Laser scanners canalso be used for some particular cases when it is desirable toilluminate some part of the scene with a bright spot. In some cases, ascanning laser rangemeter can be used in conjunction with theforward-looking cameras 204 to determine the distance to particularobjects in the camera view. Other geometries of the mapping vehicle arenot excluded from this general description of one simplifiedarrangement.

The video camera system can be used by itself with appropriate softwareas is currently being done by Lamda Tech International Inc. of Waukesha,Wis., to obtain the location of salient features of a road. However,such a method to obtain accurate maps is highly labor intensive andtherefore expensive. The cameras and associated equipment in the presentinvention are therefore primarily used to supplement the linear cameraand laser radar data acquisition systems to be described now. Thishowever is one approach with a preferred alternate approach using four,six or more cameras as described above.

In this approach, the mapping vehicle data acquisition modules willtypically contain both a linear camera and a scanning laser radar,however, for some applications one or the other may be omitted.

The linear camera 210 is a device that typically contains a linear CCD,CMOS or other light sensitive array of, for example, four thousandpixels. An appropriate lens provides a field of view to this camera thattypically extends from approximately the center of the vehicle out tothe horizon. This camera records a one-dimensional picture covering theentire road starting with approximately the center of the lane andextending out to the horizon. This linear array camera 210 thereforecovers slightly more than 90 degrees. Typically, this camera operatesusing natural illumination and produces effectively a continuous pictureof the road since it obtains a linear picture, or column of pixels, fortypically every one-inch of motion of the vehicle. Thus, a completetwo-dimensional panoramic view of the road traveled by the mappingvehicle is obtained. Since there are two such linear camera units, a 180degree view is obtained. This camera will typically record in full colorthus permitting the map database team to have a complete view of theroad looking perpendicular from the vehicle. The view is recorded in asubstantially vertical plane. This camera will not be able to read texton traffic signs, thus the need for the forward-looking cameras 208.Automated software can be used with the images obtained from thesecameras 208, 210 to locate the edge of the road, lane markers, thecharacter of land around and including the road and all areas that anerrant vehicle may encounter. The full color view allows thecharacterization of the land to be accomplished automatically withminimal human involvement.

The scanning laser radar 212 is typically designed to cover a 90 degreeor less scan thus permitting a rotating mirror to acquire at least foursuch scans per revolution. The scanning laser radar 212 can becoordinated or synchronized with the linear camera 210 so that eachcovers the same field of view with the exception that the camera 210typically will cover more than 90 degrees. Scanning laser radar 212 canbe designed to cover more or less than 90 degrees as desired for aparticular installation. The scanning laser radar 212 can operate in anyappropriate frequency from above ultraviolet to the terahertz.Typically, it will operate in the eye-safe portion of the infraredspectrum for safety reasons. The scanning laser radar 212 can operateeither as a pulse-modulated or a tone-modulated laser as is known in theart. If operating in the tone-modulated regime, the laser light will betypically modulated with three or more frequencies in order to eliminatedistance ambiguities. Noise or code modulated radar can also be used.

For each scan, the laser radar 212 provides the distance from thescanner to the ground for up to several thousand points in a verticalplane extending from approximately the center of the lane out to nearthe horizon. This device therefore provides precise distances andelevations to all parts of the road and its environment. The preciselocation of signs that were observed with the forward-looking cameras204, for example, can now be easily and automatically retrieved. Thescanning laser radar therefore provides the highest level of mappingautomation.

Scanning laser radars have been used extensively for mapping purposesfrom airplanes and in particular from helicopters where they have beenused to map portions of railway lines in the US. Use of the scanninglaser radar system for mapping roadways where the radar is mounted ontoa vehicle that is driving the road is believed to be novel to thecurrent assignee.

Ideally, all of the above-described systems are present on the mappingvehicle. Although there is considerable redundancy between the linearcamera and the scanning laser radar, the laser radar operates at oneoptical frequency and therefore does not permit the automaticcharacterization of the roadway and its environment.

As with the forward-looking cameras, it is frequently desirable to usefilters and polarizing lenses for both the scanning laser radar and thelinear camera. In particular, reflections from the sun can degrade thelaser radar system unless appropriate filters are used to block allfrequencies except frequency chosen for the laser radar.

Laser radars are frequently also referred to as ladars and lidars. Allsuch devices that permit ranging to be accomplished from a scanningsystem, including radar, are considered equivalent for the purposes ofthis invention.

3.3 Map Enhancements

Once the road edge and lane locations, and other roadway information,are transmitted to the operator, it requires very little additionalbandwidth to include other information such as the location of allbusinesses that a traveler would be interested in such as gas stations,restaurants etc. which could be done on a subscription basis. Thisconcept was partially disclosed in the '482 patent discussed above andpartially implemented in existing map databases.

Communication of information to the operator could be done eithervisually or orally as described in U.S. Pat. No. 5,177,685 or 7,126,583.Finally, the addition of a route guidance system as described in otherpatents becomes even more feasible since the exact location of adestination can be determined. The system can be configured so that avehicle operator could enter a phone number, for example, or an addressand the vehicle would be automatically and safely driven to thatlocation. Since the system knows the location of the edge of everyroadway, very little, if any, operator intervention would be required.Even a cell phone number can be used if the cell phone has the SnapTrackGPS location system as soon to be provided by Qualcomm.

Very large may databases can now reside on a vehicle as the price ofmemory continues to drop. Soon it may be possible to store the mapdatabase of an entire country on the vehicle and to update it as changesare made. The area that is within, for example, 1000 miles from thevehicle can certainly be stored and as the vehicle travels from place toplace the remainder of the database can be updated as needed though aconnection to the Internet, for example.

4. Precise Positioning

Another important aid as part of some of the inventions disclosed hereinis to provide markers along the side(s) of roadways which can be eithervisual, passive or active transponders, reflectors, or a variety ofother technologies including objects that are indigenous to or near theroadway, which have the property that as a vehicle passes the marker itcan determine the identity of the marker and from a database it candetermine the exact location of the marker. The term “marker” is meantin the most general sense. The signature determined by a continuous scanof the environment, for example, would be a marker if it is relativelyinvariant over time such as, for example, buildings in a city.Basically, there is a lot of invariant information in the environmentsurrounding a vehicle as it travels down a road toward its destination.From time to time, a view of this invariant landscape or information maybe obstructed but it is unlikely that all of it will be during thetravel of a mile, for example. Thus, a vehicle should be able to matchthe signature sensed with the expected one in the map database andthereby obtain a precise location fix. This signature can be obtainedthrough the use of radar or laser radar technologies as reportedelsewhere herein. If laser radar is used, then an IR frequency can bechosen in the eyesafe part of the spectrum. This will permit highertransmitted power to be used which, especially when used with rangegating, will permit the penetration of a substantial distance throughfog, rain or snow. See in particular Section 5 below and for example,Wang Yanli, Chen Zhe, “Scene matching navigation based on multisensorimage fusion” SPIE Vol. 5286 p. 788-793, 2003 and more recently “Backingup GNSS with laser radar & INS, RAIM in the city, antenna phasewind-up”, Inside GNDD July/August 2007.

For the case of specific markers placed on the infrastructure, if threeor more of such markers are placed along a side of the roadway, apassing vehicle can determine its exact location by triangulation. Notethat even with two such markers using radar with distance measuringcapability, the precise position of a vehicle can be determined asdiscussed below in reference to the Precise Positioning System. In fact,if the vehicle is only able to observe a single radar or lidar reflectorand take many readings as the reflector is passed, it can determinequite accurately its position based on the minimum distance reading thatis obtained during the vehicle's motion past the reflector. Although itmay be impractical to initially place such markers along all roadways,it would be reasonable to place them in particularly congested areas orplaces where it is known that a view of one or more of the GPSsatellites is blocked. A variation of this concept will be discussedbelow.

Although initially it is preferred to use the GPS navigationalsatellites as the base technology, the invention is not limited therebyand contemplates using all methods by which the location of the vehiclecan be accurately determined relative to the earth surface. The locationof the roadway boundaries and the location of other vehicles relative tothe earth surface are also to be determined and all relevant informationused in a control system to substantially reduce and eventuallyeliminate vehicle accidents. Only time and continued system developmentwill determine the mix of technologies that provide the most costeffective solution. All forms of information and methods ofcommunication to and between vehicles are contemplated including directcommunication with stationary and moving satellites, communication withfixed earth-based stations using infrared, optical, terahertz, radar,radio and other segments of the electromagnetic spectrum, direct orindirect communication with the internet and inter-vehiclecommunication. Some additional examples follow:

A pseudo-GPS can be delivered from cell phone stations, in place of orin addition to satellites. In fact, the precise location of a cell phonetower need not initially be known. If it monitors the GPS satellitesover a sufficiently long time period, the location can be determined asthe calculated location statistically converges to the exact location.Thus, every cell phone tower could become an accurate DGPS base stationfor very little cost. DGPS corrections can be communicated to a vehiclevia FM radio via a sub-carrier frequency for example. An infrared orradar transmitter along the highway can transmit road boundary locationinformation. A CD-ROM, DVD or other portable mass storage can be used atthe beginning of a controlled highway to provide road boundaryinformation to the vehicle. Finally, it is contemplated that eventuallya satellite will broadcast periodically, perhaps every five minutes, atable of dates covering the entire CONUS that provides the latest updatedate of each map segment. If a particular vehicle does not have thelatest information for a particular region where it is operating, itwill be able to use its cell phone or other communication system toretrieve such road maps perhaps through the Internet or from an adjacentvehicle. Emergency information would also be handled in a similar mannerso that if a tree fell across the highway, for example, all nearbyvehicles would be notified.

To implement map updating, a signal may be directed by the infrared orradar transmitter to the area covered by a segment of the map relatingto the latest update information for that segment in a form receivableby a transmitter on vehicles passing through the area. A processor onthe vehicle receives the signals, analyzes it and determines whether itsmap includes the latest updated map information for the segment in whichthe vehicle is presently located. If not, an update for the vehicle'smap information is downloaded via the transmitter. This embodiment isparticularly advantageous when the transmitter is arranged before asection of road and thus provides vehicles entering the road and inrange of the transmitter with the map data they will subsequently need.

The transmitter which transmits information to the vehicle, whether mapinformation or other information, may be movable and thus would beparticularly useful for roads undergoing construction, subject toclosure or blockage in view of construction or other factors, or forwhich map data is not yet available. In this case, the movable,temporary transmitter would be able to provide map data for the affectedsection of road to vehicles in range of the transmitter. As thetransmitter is moved along the roadway, the information transmitted canbe changed.

One of the possible problems with the RtZF® system described herein isoperation in areas of large cities such as lower Manhattan. In suchlocations, unless there are a plurality of local pseudolites or preciseposition location system installations or the environment signaturesystem is invoked such as with adaptive associative memories asdescribed above, the signals from the GPS satellites can besignificantly blocked. Also, there is frequently a severe multipathproblem in cities. A solution is to use the LORAN system as a backup forsuch locations. The accuracy of LORAN can be comparable to DGPS. Use ofmultiple roadway-located Precise Positioning Systems would be a bettersolution or a complementary solution. Additionally, some locationimprovement can result from application of the SnapTrack system asdescribed in U.S. Pat. No. 5,874,914 and other patents to Krasner ofSnapTrack.

The use of geo-synchronous satellites as a substitute for earth boundbase stations in a DGPS system, with carrier phase enhancements forsub-meter accuracies, is also a likely improvement to the RtZF® systemthat can have a significant effect in urban areas.

Another enhancement that would be possible with dedicated satellitesand/or earth bound pseudolites results from the greater control over theinformation transmitted than is available from the present GPS system.Recognizing that this system could save in excess of 40,000 lives peryear in the U.S. alone, the cost of deploying such special purposestations can easily be justified. For example, say there exists amodulated wave that is 10000 kilometers long, another one which is 1000km long etc. down to 1 cm. It would then be easy to determine theabsolute distance from one point to the other. The integer ambiguity ofRTK DGPS would be eliminated. Other types of modulation are of coursepossible to achieve the desired result of simply eliminating the carrierinteger uncertainty that is discussed in many U.S. patents and otherliterature. This is not meant to be a recommendation but to illustratethat once the decision has been made to provide information to everyvehicle that will permit it to always know its location within 10 cm,many technologies will be there to make it happen. The cost savingsresulting from eliminating fatalities and serious injuries will easilycover the cost of such technologies many times over. The provision ofadditional frequencies can also enhance the system and renderdifferential corrections unnecessary. Each frequency from a satellite isdiffracted differently by the ionosphere. The properties of theionosphere can thus be determined if multiple frequencies aretransmitted. This will partially be achieved with the launch of theEuropean Galileo GPS satellite system as well as others by Japan, Russiaand China in combination with the U.S. GPS system.

It is expected, especially initially, that there will be many holes inthe DGPS or GPS and their various implementations that will leave thevehicle without an accurate means of determining its location. Theinertial navigation system described above will help in filling theseholes but its accuracy is limited to a time period significantly lessthan about an hour and a distance of less than about 50 miles before itneeds correcting. That may not be sufficient to cover the period betweenDGPS availability. It is therefore contemplated that the RtZF® systemwill also make use of low cost systems located along the roadways thatpermit a vehicle to accurately determine its location.

Such a position-determination assistance system would include aplurality of transmitters placed on or alongside a road, with signalsfrom the transmitters being directed to an area in the path of atraveling vehicle to enable the vehicle to determine its position usingthe transmitted signals and information about the position of thetransmitters. Positional information about the transmitters either beingpreviously provided to the vehicle's processor, e.g., from a mapdatabase, or along with the transmission. The transmitters may be agroup of a linked MIR, IR or RF transmitters which direct signals to acommon area through which vehicles pass. Alternatively, the transmittersmay be a group of a plurality of RFID devices, in which case, one ormore interrogators are arranged on the vehicle to cause the RFID devicesto direct signals in response to an interrogation signal from theinterrogator.

One example of such a system would be to use a group of three MicropowerImpulse Radar (MIR) units such as developed by Lawrence LivermoreLaboratory.

A MIR operates on very low power and periodically transmits a very shortspread spectrum radar pulse. The estimated cost of a MIR is less than$10 even in small quantities. If three such MIR transmitters, 151, 152and 153, as shown in FIG. 11, are placed along the highway and triggeredsimultaneously or with a known delay, and if a vehicle has anappropriate receiver system, the time of arrival of the pulses can bedetermined and thus the location of the vehicle relative to thetransmitters determined. The exact location of the point where all threepulses arrive simultaneously would be the point that is equidistant fromthe three transmitters 151, 152, 153 and would be located on the mapinformation. Only three devices are required since only two dimensionsneed to be determined and it is assumed that the vehicle in on the roadand thus the vertical position is known, otherwise four MIRs would berequired. Thus, it would not even be necessary to have the signalscontain identification information since the vehicle would not be so faroff in its position determination system to confuse different locations.By this method, the vehicle would know exactly where it was whenever itapproached and passed such a triple-MIR installation. The MIR triad PPSor equivalent could also have a GPS receiver and thereby determine itsexact location over time as described above for cell phone towers. Afterthe location has been determined, the GPS receiver can be removed. Inthis case, the MIR triad PPS or equivalent could be placed at will andthey could transmit their exact location to the passing vehicles. Analternate method would be to leave the GPS receiver with the PPS time ofarrival of the GPS data from each satellite so that the passing vehiclesthat do not go sufficiently close to the PPS can still get an exactlocation fix. A similar system using RFID tags is discussed below.

Several such readings and position determinations can be made with oneapproach to the MIR installation, the vehicle need not wait until theyall arrive simultaneously. Also the system can be designed so that thesignals never arrive at the same time and still provide the sameaccuracy as long as there is a sufficiently accurate clock on board thevehicle. One way at looking at FIG. 11 is that transmitters 151 and 152fix the lateral position of the vehicle while transmitters 151 and 153fix the location of the vehicle longitudinally. The three transmitters151,152,153 need not be along the edges on one lane but could spanmultiple lanes and they need not be at ground level but could be placedsufficiently in the air so that passing trucks would not block the pathof the radiation from an automobile. Particularly in congested areas, itmight be desirable to code the pulses and to provide more than threetransmitters to further protect against signal blockage or multipath.

The power requirements for the MIR transmitters are sufficiently lowthat a simple photoelectric cell array can provide sufficient power formost if not all CONUS locations. With this exact location information,the vehicle can become its own DGPS station and can determine thecorrections necessary for the GPS. It can also determine the integerambiguity problem and thereby know the exact number of wave lengthsbetween the vehicle and the satellites or between the vehicle and theMIR or similar station. These calculations can be done on vehicle ifthere is a connection to a network, for example. This would beparticularly efficient as the network, once it had made the calculationsfor one vehicle, would have a good idea of the result for another nearbyvehicle and for other vehicles passing the same spot at a differenttime. This network can be an ad-hoc or mesh network or the internetusing WiMAX, for example. Alternately, the information can be broadcastfrom the vehicle.

MIR is one of several technologies that can be used to provide preciselocation determination. Others include the use of an RFID tag that isdesigned in cooperation with its interrogator to provide a distance tothe tag measurement. Such as RFID can be either an active device with aninternal battery or solar charger or a passive device obtaining itspower from an RF interrogation signal to charge a capacitor or aSAW-based tag operating without power. An alternate and preferred systemuses radar or other reflectors where the time of flight can be measured,as disclosed elsewhere herein.

Once a vehicle passes a Precise Positioning Station (PPS) such as theMIR triad described above, the vehicle can communicate this informationto surrounding vehicles. If the separation distance between twocommunicating vehicles can also be determined by the time-of-flight orequivalent method, then the vehicle that has just passed the triad can,in effect, become a satellite equivalent or moving pseudolite. That is,the vehicle sends (such as by reflection so as not to introduce a timedelay) its GPS data from the satellite and the receiving vehicle thengets the same message from two sources and the time difference is thetime of flight. Finally, if many vehicles are communicating theirpositions to many other vehicles along with an accuracy of positionassessment, each vehicle can use this information along with thecalculated separation distances to improve the accuracy of its positiondetermination. In this manner, as the number of such vehicles increases,the accuracy of the entire system increases until an extremely accuratepositioning system for all vehicles results. Such a system, since itcombines many sources of position information, is tolerant of thefailure of any one or even several such sources. Thus, the RtZF® systembecomes analogous to the Internet in that it cannot be shut down and thegoal of perfection is approached. Some of the problems associated withthis concept will be discussed below.

Precise Positioning was described above and relates to methods oflocating a vehicle independently of GPS within sub meter accuracy. Thiscan be done using an MIR triads; barcodes painted on the roadway; radar,laser radar or terahertz radar and infrastructure mounted reflectors;RFID markers; or through the use of matching a signature obtained fromthe environment with a stored signature using, for example, AdaptiveAssociative Memories (AAM) based on Cellular Neural Networks (CNN), forexample.

AAM is a type of neural network that is distinguished in that it can doprecise identification from poor and sparse data in contrast to ordinaryback propagation neural networks discussed elsewhere herein thatgeneralize and always give an approximate answer. Applications for AAMinclude: (1) Occupant recognition (face, iris, voice print, fingerprintsetc.), and (2) Vehicle location recognition for the RtZF® PrecisePositioning System, which is the focus here. In contrast to other PPSsystems described above, AAM permits the precise location of a vehicleon a roadway within centimeters without the use of additions to theinfrastructure. A radar, laser scanner, or terahertz radar continuouslyis projected from the vehicle toward the environment, such as theroadway to the side of the vehicle, and from the returned reflectedwaves it obtains a signature of the passing environment and compares itwith a recorded signature using ASM. This signature, for example, can bethe distance from the vehicle to the infrastructure which has beennormalized for the purpose of signature matching with some method suchas the average or some other datum. Thus it is the relative distancesignature that can be compared with a stored signature thus removing theposition of the vehicle on the roadway as a variable. When a match isfound the distance to a precise object can be determined placing thevehicle precisely on the road in both the longitudinal and lateraldimensions. As discussed above, this can make the vehicle a DGPS stationfor correction of the GPS errors but it also can be used as the primarylocation system without GPS.

Other methods can be used to precisely locate a vehicle using theinfrastructure and only one preferred method has been described herein.For example, the vertical motion signature of the vehicle can in somecases be used. This could involve determining this signature from thenatural road or a pattern of disturbances similar to a rubble strip canbe placed in the roadway and sensed by an accelerometer, microphone orother sensor. Even the signature of the magnetic or reflectiveproperties of the roadway or the environment at the side of road can becandidates with the appropriate sensors. Basically, any system thatprovides a signature indication location that is derived from theinfrastructure with appropriate sensors would qualify.

Another method, for example, is to match camera images where again anAAM can be used. Since the vehicle knows approximately where it is, therecorded signature used in the AAM will change as the vehicle moves andthus only a small amount of data need be used at a particular time. TheAAM system is fast and relatively simple. Typically twenty data pointswill be used to determine the match, for example. What follows is ageneral description of AAM

Associative (context-addressable) memory is frequently dedicated to datasearch and/or restoration from available fragments. Associativeretrieval requires minimal information on sought objects, so such amachine might be used for most complicated tasks of data identificationfor partially destroyed or corrupted images. It can be applied toauthenticity attribution, document falsification detection, messagefragment identification in the Internet etc. as well as signaturematching with the environment for PPS.

Neural associative memory works due to multi-stability of strongfeedback systems. Common models like Hopfield networks andbi-directional associative memory provide memorization by means ofcomputation network weights. It does not corrupt previously storedimages. Unfortunately, these networks cannot be widely used because oftheir low capacity and inefficient physical memory usage. A number M ofvectors memorized does not exceed 14% of the number of neurons in thenetwork N. Since a network contains N² connections, it needs storage ofat least 25M² real weight values. Implementation of this technique canbe aided through consultation of International Scientific Research inKyiv, Ukraine.

Cellular architecture can exhaustively solve the problem of physicalmemory usage. Cellular memories have band-like synaptic matrix. Thevolume (number of elements) grows linearly with respect to neuronnumber. This is why cellular neural networks (CNNs) can be useful forvery large data processing problems. Pioneering models of associativememories via CNNs were proposed in some earlier works. However, moredetailed studies showed some fundamental limitations. Indeed, it has nowbeen shown that the number of images stored is restricted by a cellsize. Hence, it does not depend on the number of neurons. A moreefficient way of redundancy reduction has also been found due toconnection selection after training. This results in the use of only asmall part of physical memory without corruption of memorized data. Thenetwork after weight selection looks like the cellular one; so bycombining cellular training algorithms and weight selection, a novelnetwork paradigm has resulted. It is an adaptive neural paradigm withgreat memorizing capacity.

At present, some breakthrough associative memories have been implementedin a software package available from the current assignee. The resultscan be applied for processing of large databases, real-time informationretrieval, PPS etc. Other applications for this technology include face,iris, fingerprint, voiceprint, character, signature, etc. recognition.

FIG. 11 shows the implementation of the invention using the PrecisePositioning System (PPS) 151, 152, 153, in which a pair of vehicles 18,26 are traveling on a roadway each in a defined corridor delineated bylines 14 and each is equipped with a system in accordance with theinvention and in particular, each is equipped with PPS receivers. Fourversions of the PPS system will now be described. This invention is notlimited to these examples but they will serve to illustrate theprincipals involved.

Vehicle 18 contains two receivers 160,161 for the micropower impulseradar (MIR) implementation of the invention. MIR or ultrawideband (UWB)transmitter devices are placed at locations 151, 152 and 153respectively. They are linked together with a control wire, not shown,or by a wireless connection such that each device transmits a shortradar or RF pulse at a precise timing relative to the others. Thesepulses can be sent simultaneously or at a precise known delay. Vehicle18 knows from its map database the existence and location of the threeMIR transmitters. The transmitters 151,152 and 153 can either transmit acoded pulse or non-coded pulse. In the case of the coded pulse, thevehicle PPS system will be able to verify that the three transmitters151, 152, 153 are in fact the ones that appear on the map database.Since the vehicle will know reasonably accurately its location and it isunlikely that other PPS transmitters will be nearby or within range, thecoded pulse may not be necessary. Two receivers 160 and 161 areillustrated on vehicle 18. For the MIR implementation, only a singlereceiver is necessary since the position of the vehicle will be uniquelydetermined by the time of arrival of the three MIR pulses. A secondreceiver can be used for redundancy and also to permit the vehicle todetermine the angular position of the MIR transmitters as a furthercheck on the system accuracy. This can be done since the relative timeof arrival of a pulse from one of the transmitters 151, 152, 153 can beused to determine the distance to each transmitter and by geometry itsangular position relative to the vehicle 18. If the pulses are coded,then the direction to the MIR transmitters 151, 152, 153 will also bedeterminable.

The micropower impulse radar units require battery power or anotherpower mechanism to operate. Since they may be joined together with awire in order to positively control the timing of the three pulses, asingle battery can be used to power all three units. This battery canalso be coupled with a solar panel to permit maintenance free operationof the system. Since the MIR transmitters use very small amounts ofpower, they can operate for many years on a single battery.

Although the MIR systems are relatively inexpensive, on the order of tendollars each, the installation cost of the system will be significantlyhigher than the RFID and radar reflector solutions discussed next. TheMIR system is also significantly more complex than the RFID system;however, its accuracy can be checked by each vehicle that uses thesystem. Tying the MIR system to a GPS receiver and using the accurateclock on the GPS satellites as the trigger for the sending of the radarpulses can add additional advantages and complexity. This will permitvehicles passing by to additionally accurately set their clocks to be insynchronization with the GPS clocks. Since the MIR system will know itsprecise location, all errors in the GPS signals can be automaticallycorrected and in that case, the MIR system becomes a differential GPSbase station. For most implementations, this added complexity is notnecessary since the vehicle themselves will be receiving GPS signals andthey will also know precisely their location from the triad of MIRtransmitters 151, 152, 153.

A considerably simpler alternate approach to the MIR system describedabove utilizes reflective RFID tags. These tags, when interrogated by aninterrogator type of receiver 160, 161, reflect or retransmit after aknown delay a modified RF signal with the modification being theidentification of the tag. Such tags are described in many patents andbooks on RFID technology and can be produced for substantially less thanone dollar each. The implementation of the RFID system would involve theaccurate placement of these tags on known objects on or in connectionwith infrastructure. These objects could be spots on the highway, posts,signs, sides of buildings, poles, in highway reflectors or structuresthat are dedicated specifically for this purpose. In fact, any structurethat is rigid and unlikely to change position can be used for mountingRFID tags. In downtown Manhattan, building sides, street lights,stoplights, or other existing structures are ideal locations for suchtags. A vehicle 18 approaching a triad of such RFID tags represented by151, 152, 153 would transmit an interrogation pulse from interrogator160 and/or 161. The pulse would reflect off of, or be retransmitted by,each tag within range and the signal would be received by the sameinterrogator(s) 160, 161 or other devices on the vehicle. Once again, asingle interrogator is sufficient. It is important to note that therange to RFID tags is severely limited unless a source of power isprovided. It is very difficult to provide enough power from RF radiationfrom the interrogator for distances much greater than a few feet. Forlonger distances, a power source should be provided which can be abattery, connection to a power line, solar power, energy harvested fromthe environment via vibration, for example, unless the RFID is based onSAW technology. For SAW technology, reading ranges may be somewhatextended. Greater distances can be achieved using reflectors orreflecting antennas.

Electronic circuitry, not shown, associated with the interrogator 160and/or 161 would determine the precise distance from the vehicle to theRFID tag 151, 152, 153 based on the round trip time of flight and anyretransmission delay in the RFID. This will provide the precise distanceto the three RFID tags 151, 152, 153. Once again, a second interrogator161 can also be used, in which case, it could be a receiver only andwould provide redundancy information to the main interrogator 160 andalso provide a second measure of the distance to each RFID tag. Based onthe displacement of the two receivers 160, 161, the angular location ofeach RFID tag relative into the vehicle can be determined providingfurther redundant information as to the position of the vehicle relativeto the tags.

Radar corner or dihedral reflectors can be placed on poles or otherconvenient places such that a radar or laser beam pointed upwards at anangle, such as 30 to 45 degrees from the vehicle, will cause the beam toilluminate the reflector and thereby cause a reflection to return to thevehicle. Through well-known methods, the distance to the reflector canbe accurately measured with pulse radar, modulated radar and phasemeasurements or noise radar and correlations measurements. In such amanner, the host vehicle can determine its position relative to one ormore such reflectors and if the location of the reflector(s) is knownand recorded on the map database, the vehicle can determine its positionto within about 2 centimeters. The more reflectors that are illuminated,the better the accuracy of vehicle location determination. Thereflectors can be simple corner or dihedral reflectors or a group ofreflectors can be provided giving a return code to the host vehicle. Acode should not be necessary as the vehicle should know the approximatelocation of the reflector from map data. A description of dihedralreflectors is set forth in U.S. Pat. No. 7,089,099, incorporated byreference herein. Briefly, a dihedral reflector rotates a polarized beamon reflection by some angle such as 90 degrees. This makes it easier tolocate the reflector from other objects that might also reflect theradar or optical beam, or other electromagnetic transmission.

Using the PPS system, a vehicle can precisely determine its locationwithin about two centimeters relative to the MIR, RFID tags or radar andreflectors and since the precise location of these devices haspreviously been recorded on the map database, the vehicle will be ableto determine its precise location on the surface of the earth. With thisinformation, the vehicle will thereafter be able to use the carrier wavephase to maintain its precise knowledge of its location, as discussedabove, until the locks on the satellites are lost. This prediction ofphase relies on the vehicle system being able to predict the phase ofthe signal from a given satellite that is reaching a fixed location suchas the location that the vehicle was in when it was able to determineits position precisely. This requires an accurate knowledge on thesatellite orbits and an accurate clock. Given this information, thevehicle system should be able to determine the phase of a satellitesignal at the fixed location and at its new location and, by comparingthe phase from such a calculation from each satellite, it should be ableto precisely determine its position relative to the fixed location.Errors due to changes in the ionosphere and the vehicle clock accuracywill gradually degrade the accuracy of these calculations. The vehicle18 can broadcast this information to vehicle 26, for example, permittinga vehicle that has not passed through the PPS triad to also greatlyimprove the accuracy with which it knows its position. Each vehicle thathas recently passed through a PPS triad now becomes a differential GPSstation for as long as the satellite locks are maintained assuming aperfect clock on-board the vehicle and a stable ionosphere. Therefore,through inter-vehicle communications, all vehicles in the vicinity canalso significantly improve their knowledge of their position accuracyresulting in a system which is extremely redundant and therefore highlyreliable and consistent with the “Road to Zero Fatalities”™ process.Once this system is operational, it is expected that the U.S. governmentand other governments will launch additional GPS type satellites, eachwith more civilian readable frequencies, or other similar satellitesystems, further strengthening the system and adding further redundancyeventually resulting in a highly interconnected system that approaches100% reliability and, like the Internet, cannot be shut down.

As the system evolves, the problems associated with urban canyons,tunnels, and other obstructions to satellite view will be solved by theplacement of large numbers of PPS stations, or other devices providingsimilar location information.

Another PPS system uses reflected energy from the environment to createa signature that can be matched with a recorded signature using atechnology such as adaptive associative memories (AAM), or equivalentincluding correlation. Since the AAM was discussed above, thecorrelation system will be discussed here. As the mapping vehicletraverses the roadway, it can record the distance to various roadsideobjects as a continuous signal having peaks and valleys. In fact,several such signatures can economically be recorded such thatregardless of where on the roadway a subsequent vehicle appears, it willrecord a similar signature. The signature can be enhanced if dualfrequency terahertz is used since the reflectance from an object canvary significantly from one terahertz frequency to another depending onthe composition of the object. Thus, for one frequency, a metal and awood object may both be highly reflective while at another frequency,there can be a significant difference. Significantly more information isavailable when more than one frequency is used. Another preferredapproach is to use eye-safe IR.

Using the correlation system, a vehicle will continuously be comparingits received signature at a particular location to the previouslyrecorded signature and shifting the two relative to each other until thebest match occurs. Since this will be done continuously and since wewill know the velocity of the vehicle, it should never deviatesignificantly from the recorded position and thus the vehicle willalways have a non-GPS method of determining its exact location. Thereare certain areas where the signature matching may be problematic suchas going by a wheat field or the ocean. Fortunately, such wide openspaces are precisely where the GPS satellite system should work best andsimilarly, the places where the signature method works best is where theGPS has problems. Thus, the systems are complementary. In most places,both systems will work well providing a high degree of redundancy.

Many mathematical methods exist for determining the best shift of thetwo signatures (the previously recorded one and a new one) and thereforethe various correlation methods will not be presented here.

Although the system has been illustrated for use with automobiles, thesame system would apply for all vehicles including trucks, trains aneven airplanes taxiing on runways. It also would be useful for use withcellular phones and other devices carried by humans. The combination ofthe PPS system and cellular phones permits the precise location of acellular phone to be determined within centimeters by an emergencyoperator receiving a 911 call, for example. Such RFID tags can beinexpensively placed both inside and outside of buildings, for example.

The range of RFID tags is somewhat limited to a few meters for currenttechnology. If there are obstructions preventing a clear view of theRFID tag by the interrogator, the distance becomes less. For someapplications where it is desirable to use larger distances, batterypower can be provided to the RFID tags. In this case, the interrogatorwould send a pulse to the tag that would turn on the tag and at aprecise, subsequent time, the tag would transmit an identificationmessage. In some cases, the interrogator itself can provide the power todrive the RFID circuitry, in which case the tag would again operate inthe transponder mode as opposed to the reflective mode.

The RFID tags discussed herein can be either the electronic circuit orSAW designs.

From the above discussion, those skilled in the art will understand thatother devices can be interrogated by a vehicle traveling down the road.Such devices might include various radar types or designs of reflectors,mirrors, other forms of transponders, or other forms of energyreflectors. All such devices are contemplated by this invention and theinvention is not limited to be specific examples described. Inparticular, although various frequencies including radar, terahertz andinfrared have been discussed, this invention is not limited to thoseportions of the electromagnetic spectrum. In particular the X-ray bandof frequencies may have some particular advantages for some external andinterior imaging applications.

Any communication device can be coupled with an interrogator thatutilizes the MIR, radar or RFID PPS system described above. Many devicesare now being developed that make use of the Bluetooth communicationspecification. All such Bluetooth-enabled devices can additionally beoutfitted with a PPS or GPS system permitting the location of theBluetooth device to be positively determined. This enabling technologywill permit a base station to communicate with a Bluetooth-enabled orsimilar device whose location is unknown and have the device transmitback its location. As long as the Bluetooth-enabled device is within therange of the base station or internet, its location can be preciselydetermined. Thus, the location of mobile equipment in a factory,packages within the airplane cargo section, laptop computers, cellphones, PDAs, and eventually even personal glasses or car keys or anydevice upon which a Bluetooth-enabled or similar device can be attachedcan be determined. Actually, this invention is not limited to Bluetoothdevices but encompasses any device that can communicate with any otherdevices. An example of such a Bluetooth device is the Wibree device thatsends out a periodic signal that can be received by a receiver that hasan internet connection. A ubiquitous internet such as WiMAX, forexample, can be such a device. A set of car keys, a pair of glasses in acase, a wallet, a cell phone which has been turned off or whose batteryhas run down can be equipped with a Wibree type device and its positionrecorded on the internet, providing the device is in range of areceiver, so that when the owner is searching for the item, he or sheneed only log onto the internet to find its location. A similar systemcan be used for any asset regardless how large or small it is and theWibree device can be independent of external power and yet exist foryears on a single battery charge due to its low duty cycle.

Once the location of an object can be determined, many other servicescan be provided. These include finding the device, or the ability toprovide information to that device or to the person accompanying thatdevice such as the location of the nearest bathroom, restaurant, or theability to provide guided tours or other directions to people travelingto other cities, for example.

A particularly important enhancement to the above-described system usesprecise positioning technology independent of GPS. The precisepositioning system, also known as the calibration system, generallypermits a vehicle to precisely locate itself independently of the IMU orDGPS systems.

One example of this technology involves the use of a radar or lidar andreflector system wherein radar or lidar transceivers are placed on thevehicle that send radar or lidar waves to reflectors that are mounted atthe side of road. The location of reflectors either is already preciselyknown or is determined by the mapping system during data acquisitionprocess. The radar or lidar transceivers transmit a pulse, code orfrequency or noise modulated radar or lidar signal to the road-mountedreflectors, typically corner or dihedral reflectors, which reflect asignal back to the radar or lidar transceiver. This permits the radar orlidar system to determine the precise distance from the transceiver tothe reflector by either time-of-flight or phase methods. Note thatalthough “radar” will be used below in the illustrations, terahertz orlidar can also be used and thus the word “radar” will be used to coverappropriate parts of the electromagnetic spectrum.

In one possible implementation, each vehicle is equipped with two radardevices operating in the 24-77 GHz portion of the spectrum. Each radarunit will be positioned on the vehicle and can be aimed outward,slightly forward and up toward the sides of the roadway. Poles would bepositioned along the roadway at appropriate intervals and would havemultiple corner cube or dihedral radar reflectors mounted thereon tothereto, possibly in a vertical alignment. The lowest reflector on thepole can be positioned so that the vehicle radar will illuminate thereflector when the vehicle is in the lane closest to the pole. Thehighest reflector on the pole can be positioned so that the vehicleradar will illuminate the reflector when the vehicle is in the lane mostremote from the pole. The frequency of the positioning of the poles willbe determined by such considerations as the availability of light polesor other structures currently in place, the probability of losing accessto GPS satellites, the density of vehicle traffic, the accuracy of theIMU and other similar considerations. Initially, rough calculations havefound that a spacing of about ¼ mile would likely be acceptable.

If the precise location of the reflectors has been previously determinedand is provided on a road map database, then the vehicle can use thisinformation to determine its precise location on the road. In a moretypical case, the radar reflectors are installed and the mapping vehicleknows its location precisely from the differential GPS signals and theIMU, which for the mapping vehicle is typically of considerably higheraccuracy than will be present in the vehicles that will later use thesystem. As a result, the mapping vehicle can also map a tunnel, forexample, and establish the locations of radar reflectors that will laterbe used by non-mapping vehicles to determine their precise location whenthe GPS and differential GPS signals are not available. Similarly, suchradar reflectors can be located for an appropriate distance outside ofthe tunnel to permit an accurate location determination to be made by avehicle until it acquires the GPS and differential GPS signals. Such asystem can also be used in urban canyons and at all locations where theGPS signals can be blocked or are otherwise not available. Since thecost of radar reflectors is very low, it is expected that eventuallythey will be widely distributed on roads in the U.S.

Use of radar and reflectors for precise positioning is only one of manysystems being considered for this purpose. Others include markings onroadway, RFID tags, laser systems, laser radar and reflectors, magnetictags embedded in the roadway, magnetic tape, etc. The radar andreflector technology has advantages over some systems in that it is notseriously degraded by bad weather conditions, is not affected if coveredwith snow, does not pose a serious maintenance problem, and other costand durability features. Any movement in the positioning of thereflectors can be diagnosed from vehicle PPS-mounted systems.

The radar transceivers used are typically mounted on either side ofvehicle and pointed upward at between 30 and 60 degrees. They aretypically aimed so that they project across the top of the vehicle sothat several feet of vertical height can be achieved prior to passingover adjacent lanes where the signal could be blocked by a truck, forexample. Other mounting and aiming systems can be used.

The radar reflectors are typically mounted onto a pole, building,overpass, or other convenient structure. They can provide a return codeby the placement of several such reflectors such that the reflectedpulse contains information that identifies this reflector as aparticular reflector on the map database. This can be accomplished innumerous ways including the use of a collection of radar reflectors in aspaced-apart geometric configuration on a radius from the vehicle. Thepresence or absence of a reflector can provide a returned binary code,for example.

Operation of the system is as follows. A vehicle traveling down aroadway in the vicinity of the reflector poles would transmit radar orlidar pulses at a frequency of perhaps once per microsecond. These radarpulses would be encoded, perhaps with noise or code modulation, so thateach vehicle knows exactly what radar or lidar returns are from itstransmissions. As the vehicle approaches a reflector pole, it will beginto receive reflections based on the speed of the vehicle. By observing aseries of reflections, the vehicle software can select either themaximum amplitude reflection or the average or some other scheme todetermine the proper reflection to consider. The radar pulse will alsobe modulated to permit a distance to the reflector calculation to bemade based on the phase of the returned signal or through correlation.Thus, as a vehicle travels down the road and passes a pair of reflectorpoles on either side of the roadway, for example, it will be able todetermine its longitudinal position on the roadway based on the pointingangle of the radar devices and the selected maximum return as describedabove. It will also be able to determine its lateral position on theroadway based on the measured distance from the radar to the reflector.

Each reflector pole can have multiple reflectors determined byintersections of the radar or lidar beam from the vehicle traveling inthe closest and furthest lanes. The spacing of reflectors on the polewould be determined by the pixel diameter of the radar or lidar beam.For example, a typical situation may require reflectors beginning at 4 mfrom the ground and ending at 12 m with a reflector every one-meter. Forthe initial demonstrations, it is expected that existing structures willbe used. The corner cube or dihedral radar reflectors are veryinexpensive so therefore the infrastructure investment will be small aslong as existing structures can be used. In the downtown areas ofcities, buildings etc. can also be used as reflector locations.

To summarize this aspect of the invention, an inexpensive infrastructureinstallation concept is provided which will permit a vehicle to send aradar or lidar pulse and receive a reflection wherein the reflection isidentifiable as the reflection from the vehicle's own radar or lidar andcontains information to permit an accurate distance measurement. Thevehicle can thus locate itself accurately longitudinally and laterallyalong the road. A variation of the PPS system using a signature from acontinuously reflected laser or radar has been discussed above and willnot be repeated here.

FIG. 19 shows a variety of roads and vehicles operating on those roadsthat are in communication with a vehicle that is passing through aPrecise Positioning Station (PPS). The communication system used isbased on noise modulated spread spectrum technologies such as describedin papers by Lukin et al. listed in the parent '445 application.Determination of the presence of any of the PPS devices enables thevehicle to know its approximate location which is sufficient fornavigation purposes when the GPS signals are blocked, unreliable orotherwise not useable or the vehicle does not have a GPS receiver.

FIG. 20 shows a schematic of the operation of a communication and/orinformation transmission system and method in accordance with theinvention. Transmitters are provided, for example at fixed locationsand/or in vehicles or other moving objects, and data about eachtransmitter, such as its location and an identification marker, isgenerated at 240. The location of the transmitter is preferably its GPScoordinates as determined, for example, by a GPS-based positiondetermining system (although other position determining systems canalternatively or additionally be used). The data may include, when thetransmitter is a moving vehicle, the velocity, speed, the direction oftravel, the estimated travel path and the destination of the vehicle.The data is encoded at 242 using coding techniques such as thosedescribed above, e.g., phase modulation of distance or time between codetransmissions, phase or amplitude modulation of the code sequencesthemselves, changes of the polarity of the entire code sequence or theindividual code segments, or bandwidth modulation of the code sequence.The coded data is transmitted at 244 using, e.g., noise or pseudo-noiseradar.

Instead of data about each transmitter being generated at 240, generaldata for transmission could also be generated such as road conditioninformation or traffic information.

A vehicle 246 includes an antenna 248 coupled to a control module,control unit, processor or computer 250. The antenna, which can be animager, 248 receives transmissions (waves or wireless signals) includingtransmissions 252 when in range of the transmitters. The processor 250analyzes the transmissions 252. Such analysis may include adetermination as to whether any transmissions are from transmitterswithin a pre-determined area relative to the vehicle, whether anytransmissions are from transmitters situated within a pre-determineddistance from the vehicle, whether any transmissions are fromtransmitters traveling in a direction toward the vehicle's currentposition, whether any transmissions are from transmitters traveling in adirection toward the vehicle's projected position based on its currentposition and velocity, the angle between the transmitter and thevehicle, and any combinations of such determinations. In general, theinitial analysis may be any position-based filtering, location-basedfiltering, and/or motion-based filtering. Other analyses could bewhether any transmissions are from particular transmitters which mightbe dedicated to the transmission of road conditions data, traffic data,map data and the like. Once the processor 250 ascertains a particulartransmission from a transmitter of interest (for operation of thevehicle, or for any other pre-determined purpose), it extracts theinformation coded in the transmission, but preferably does not extractinformation coded in transmission from transmitters which are not ofinterest, e.g., those from transmitters situated at a location outsideof the pre-determined area. It knows the code because the code isprovided by the transmission, i.e., the initial part of the transmission252 a contains data on the location of the transmitter and the code isbased on the location of the transmitter. As such, once the initial partof the transmission 252 a is received and the location of thetransmitter extracted, the code for the remainder of the transmission252 b can be obtained.

In this manner, the extraction of information from radio frequency wavetransmission may be limited based on a threshold determination (a filterof sorts) as to whether the transmission is of potential interest, e.g.,to the operation of the vehicle based on its position, location and/ormotion. To enable this threshold determination from the analysis of thewaves or filtering of information, the initial part of the transmission252 a can be provided with positional or location information about thetransmitter and information necessitated by the information transferringarrangement (communication protocol data) and the remainder of thetransmission 252 b provided with additional information of potentialinterest for operation of the vehicle. The information contained ininitial part of each transmission (or set of waves) is extracted todetermine whether the information in the final part of the transmissionis of interest. If not, the information in the final part of thetransmission is not extracted. This reduces processing time and avoidsthe unnecessary extraction of mostly if not totally irrelevantinformation. An information filter is therefore provided.

Generating the transmission based on a code derived from the position ofthe transmitter, and thus the vehicle or infrastructure in which or towhich it is fixed, provides significant advantages as discussed above.The code required for spread spectrum, UWB or other communicationsystems is thus determined according to the position of the transmitter,and can be accomplished in several different ways, some of which aredisclosed elsewhere herein. However, use of coded transmissions is notrequired in all embodiments of the information transferring method andarrangement.

An additional way for vehicle-mounted transmitters is to supply positioninformation to a vehicle at an entrance to a highway or other entry andexit-limited roadway, in a wireless manner as described herein, andderiving the position information about the vehicle based on theinitially provided information when the vehicle enters the highway andinformation about the speed of the vehicle or the distance the vehicletravels. The latter quantities are determined by systems on the vehicleitself. Thus, it becomes possible to extrapolate the current position ofthe vehicle based on the initially provided position information and thespeed and/or traveling distance of the vehicle, using common physicsequations relating to motion of an object as known to those skilled inthe art. Even if the current position of the vehicle is not precise dueto, for example, variations in the highway, the system is stilloperational and effective since all vehicles on the same highway aredetermining their position relative to the entrance. This embodiment maybe considered a simpler system than described above wherein the positionof the vehicle is determined using, for example, GPS-based systems.Basically, all vehicles on the same highway receive only a singlewireless transmission when they enter the highway and update theirposition based on the distance traveled and/or speed of travel.

Further, the antenna 248 serves as a transmitter for transmittingsignals generated by the processor 250. The processor 248 is constructedor programmed to generate transmissions or noise signals based on itslocation, determined by a position determining device 254 in any knownmanner including those disclosed herein, and encode information aboutthe vehicle in the signals. The information may be an identificationmarker, the type of vehicle, its direction, its velocity or speed, itsproposed course, its occupancy, etc. The processor 248 can encode theinformation in the signals in a variety of methods as disclosed above inthe same manner that the data about the transmitter is encoded. Thus,the processor 248 not only interprets the signals and extractsinformation, it also is designed to generate appropriate noise orotherwise coded signals which are then sent from the antenna 248.

Consider the case where the automobile becomes a pseudolite or a DGPSequivalent station since it has just determined its precise locationfrom the PPS. Thus the vehicle can broadcast just like a pseudolite. Asthe vehicle leaves the PPS station, its knowledge of its absoluteposition will degrade with time depending on the accuracy of its clockand inertial guidance system and perhaps its view of the satellites orother pseudolites. In some cases, it might even be possible to eliminatethe need for satellites if sufficient PPS positions exist.

Another point is that the more vehicles that are in the vicinity of aPPS, the higher the likelihood that one of the vehicles will knowprecisely where it is by being at or close to the PPS and thus the moreaccurately every vehicle in the vicinity would know its own location.Thus, the more vehicles on the road, the accuracy with which everyvehicle knows its location increases. When only a single vehicle is onthe road, then it really doesn't need to know its position nearly asaccurately at least with regard to other vehicles. It may still need toknow its accuracy to a comparable extent with regard to the road edges.

5. Radar and Laser Radar Detection and Identification of ObjectsExternal to the Vehicle

5.1 Sensing of Non-RtZF® Equipped Objects

Vehicles with the RtZF® system in accordance with the invention ideallyshould also be able to detect those vehicles that do not have the systemas well as pedestrians, animals, bicyclists, and other hazards that maycross the path of the equipped vehicle.

Systems based on radar have suffered from the problem of being able tosufficiently resolve the images which are returned to be able toidentify the other vehicles, bridges, etc. except when they are close tothe host vehicle. One method used for adaptive cruise control systems isto ignore everything that is not moving. This, of course, leads toaccidents if this were used with the instant invention. The problemstems from the resolution achievable with radar unless the antenna ismade very large or the object is close. Since this is impractical foruse with automobiles, only minimal collision avoidance can be obtainedusing radar.

Optical systems can provide the proper resolution but may requireillumination with a bright light or laser. If the laser is in theoptical range, there is a danger of causing eye damage to pedestrians orvehicle operators. At a minimum, it will be distracting and annoying toother vehicle operators. A laser operating in the infrared part of theelectromagnetic spectrum avoids the eye danger problem, provided thefrequency is sufficiently far from the visible, and, since it will notbe seen, it will not be annoying. If the IR light is sufficientlyintense to provide effective illumination for the host vehicle, it mightbe a source of blinding light for the system of another vehicle.Therefore a method of synchronization may be required. This could takethe form of an Ethernet protocol, for example, where when one vehicledetects a transmission from another then it backs off and transmits at arandom time later. The receiving electronics would then only be activewhen the return signal is expected. Transmission can also besynchronized based on the GPS time and a scheme whereby two nearbyvehicles would transmit at different times. Since the transmissionduration can be very short, since the intensity of the IR can be high ifit is in the eye-safe range, many adjacent vehicles can transmit eachfraction of a second without interfering with each other.

Another problem arises when multiple vehicles are present that transmitinfrared at the same time if there is a desire to obtain distanceinformation from the scene. In this case, each vehicle needs to be ableto recognize its transmission and not be fooled by transmissions fromanother vehicle. This can be accomplished, as discussed above, throughthe modulation scheme. Several such schemes would suffice with apseudo-noise or code modulation as a preferred method for the presentinvention. This can also be accomplished if each vehicle accuratelyknows its position and controls its time of transmission according to analgorithm that time multiplexes transmissions based on the geographicallocation of the vehicle. Thus, if multiple vehicles are sensed in agiven geographical area, they each can control their transmissions basedon a common algorithm that uses the GPS coordinates of the vehicle toset the time slot for transmission so as to minimize interferencebetween transmissions from different vehicles. Other multiplexingmethods can also be used such as FDMA, CDMA or TDMA, any of which can bebased on the geographical location of the vehicles.

Infrared and terahertz also have sufficient resolution so that patternrecognition technologies can be employed to recognize various objects,such as vehicles, in the reflected image as discussed above. Infraredhas another advantage from the object recognition perspective. Allobjects radiate and reflect infrared. The hot engine or tires of amoving vehicle in particular are recognizable signals. Thus, if the areaaround a vehicle is observed with both passive and active infrared, moreinformation can be obtained than from radar, for example. Infrared isless attenuated by fog than optical frequencies, although it is not asgood as radar. Infrared is also attenuated by snow but at the properfrequencies it has about five times the range of human sight. Terahertzunder some situations has an effective range of as much as severalhundred times that of human sight. Note, as with radar, Infrared andterahertz can be modulated with noise, pseudonoise, or other distinctivesignal to permit the separation of various reflected signals fromdifferent transmitting vehicles.

An example of such an instrument is made by Sumitomo Electric and issufficient for the purpose here. The Sumitomo product has beendemonstrated to detect leaves of a tree at a distance of about 300meters. The product operates at a 1.5 micron wavelength.

This brings up a philosophical discussion about the trade-offs betweenradar with greater range and infrared laser radar, or lidar, with morelimited range but greater resolution. At what point should drivingduring bad weather conditions be prohibited? If the goal of ZeroFatalities™ is to be realized, then people should not be permitted tooperate their vehicles during dangerous weather conditions. This mayrequire closing roads and highways prior to the start of suchconditions. Under such a policy, a system which accurately returnsimages of obstacles on the roadway that are two to five times the visualdistance should be adequate. In such a case, radar would not benecessary.

5.2 Laser and Terahertz Radar Scanning System

Referring to FIG. 25, a digital map 116 can be provided and when thevehicle's position is determined 118, e.g., by a GPS-based system, thedigital map can be used to define the field 122 that the laser orterahertz radar scanner 102 will interrogate.

Note, when the term scanner is used herein, it is not meant to implythat the beam is so narrow as to require a back and forth motion (ascan) in order to completely illuminate an object of interest. To thecontrary, inventions herein are not limited to a particular beamdiameter other than that required for eye safety. Also a scanner may belimited to an angular motion that just covers a vehicle located 100meters, for example, from the transmitting vehicle, which may involve noangular motion of the scanner at all, or to an angular motion thatcovers 90 or more degrees of the space surrounding the transmittingvehicle. Through the use of high-powered lasers and appropriate optics,an eye safe laser beam can be created that is 5 cm in diameter, forexample, with a divergence angle less than one degree. Such an infraredspotlight requires very little angular motion to illuminate a vehicle at100 meters, for example.

Generally herein, when laser radar, or lidar, is used it will also meana system based on terahertz where appropriate. The laser radar or lidarscanner will return information as to distance to an object in thescanned field, e.g., laser beam reflections will be indicative ofpresence of object in path of laser beam 104 and from these reflections,information such as the distance between the vehicle and the object canbe obtained. This will cover all objects that are on or adjacent to thehighway. The laser pulse can be a pixel that is two centimeters or 1meter in diameter at 50 meters, for example and that pixel diameter canbe controlled by the appropriate optical system that can includeadaptive optics and liquid lenses (such as described in “Liquid lenspromises cheap gadget optics”, NewScientist.com news service, Mar. 8,2004).

The scanner should scan the entire road at such a speed that motion ofthe car can be considered insignificant. Alternately, a separate aimingsystem that operates at a much lower speed, but at a speed to permitcompensation for the car angle changes, may be provided. Such an aimingsystem is also necessary due to the fact that the road curves up anddown. Therefore two scanning methods, one a slow, but for large anglemotion and the other fast but for small angles may be required. Thelarge angular system requires a motor drive while the small angularsystem can be accomplished through the use of an acoustic wave system,such as Lithium Niobate (LiNbO₃), which is used to drive a crystal whichhas a large refractive index such as Tellurium dioxide. Other acousticoptical systems can also be used as scanners.

For these systems, frequently some means is needed to stabilize theimage and to isolate it from vehicle vibrations. Several suchstabilization systems have been used in the past and would be applicablehere including a gyroscopic system that basically isolates the imagingsystem from such vibrations and keeps it properly pointed, apiezoelectric system that performs similarly, or the process can beaccomplished in software where the image is collected regardless of thevibration but where the image covers a wider field of view then isnecessary and software is used to select the region of interest.

Alternately, two systems can be used, a radar system for interrogatinglarge areas and a laser radar for imaging smaller areas. Either or bothsystems can be range gated and noise or pseudonoise modulated.

The laser radar scanner can be set up in conjunction with a range gate106 so that once it finds an object, the range can be narrowed so thatonly that object and other objects at the same range, 65 to 75 feet forexample, are allowed to pass to the receiver. In this way, an image of avehicle can be separated from the rest of the scene for identificationby pattern recognition software 108. Once the image of the particularobject has been captured, the range gate is broadened, to about 20 to500 feet for example, and the process repeated for another object. Inthis manner, all objects in the field of interest to the vehicle can beseparated and individually imaged and identified. Alternately, a schemebased on velocity can be used to separate a part of one object from thebackground or from other objects. The field of interest, of course, isthe field where all objects with which the vehicle can potentiallycollide reside. Particular known and mapped features on the highway canbe used as aids to the scanning system so that the pitch and perhapsroll angles of the vehicle can be taken into account.

Once the identity of the object is known, the potential for a collisionbetween the vehicle and that object and/or consequences of a potentialcollision with that object are assessed, e.g., by a control module,control unit or processor 112. If collision is deemed likely,countermeasures are effected 114, e.g., activation of a driver alertsystem and/or activation of a vehicle control system to alter the travelof the vehicle (as discussed elsewhere herein).

Range gates can be achieved as high speed shutters by a number ofdevices such as liquid crystals, garnet films, Kerr and Pockel cells oras preferred herein as described in patents and patent applications of3DV Systems Ltd., Yokneam, Israel including U.S. Pat. No. 6,327,073,U.S. Pat. No. 6,483,094, US2002/0185590, WO98/39790, WO97/01111,WO97/01112 and WO97/01113.

Prior to the time that all vehicles are equipped with the RtZF® systemdescribed above, roadways will consist of a mix of vehicles. In thisperiod, it will not be possible to totally eliminate accidents. It willbe possible to minimize the probability of having an accident however,if a laser radar system similar to that described in U.S. Pat. No.5,529,138 (Shaw) with some significant modifications is used, or thosedescribed more recently in various patents and patent applications ofFord Global Technologies such as U.S. Pat. Nos. 6,690,017 and 6,730,913,and U.S. Pat. Appl. Publ. Nos. 2003/0034462, 2003/0155513 and2003/0036881. It is correctly perceived by Shaw that the dimensions of aradar beam are too large to permit distinguishing various objects whichmay be on the roadway in the path of the instant vehicle. Laser radarprovides the necessary resolution that is not provided by radar. Laserradar as used in the present invention however would acquiresignificantly more data than anticipated by Shaw. Sufficient data infact would be attained to permit the acquisition of a three-dimensionalimage of all objects in the field of view. The X and Y dimensions ofsuch objects would, of course, be determined knowing the angularorientation of the laser radar beam. The longitudinal or Z dimension canbe obtained by such methods as time-of-flight of the laser beam to aparticular point on the object and reflected back to the detector, byphase methods or by range gating. All such methods are describedelsewhere herein and in patents listed above.

At least two methods are available for resolving the longitudinaldimension for each of the pixels in the image. In one method, a laserradar pulse having a pulse width of one to ten nanoseconds, for example,can be transmitted toward the area of interest and as soon as thereflection is received and the time-of-flight determined, a new pulsewould be sent at a slightly different angular orientation. The laser,therefore, would be acting as a scanner covering the field of interest.A single detector could then be used, if the pixel is sufficientlysmall, since it would know which pixel was being illuminated. Thedistance to the reflection point could be determined by time-of-flightthus giving the longitudinal distance to all points in view on theobject.

Alternately, the entire area of interest can be illuminated and an imagefocused on a CCD or CMOS array. By checking the time-of-flight to eachpixel, one at a time, the distance to that point on the vehicle would bedetermined. A variation of this would be to use a garnet crystal as apixel shutter and only a single detector. In this case, the garnetcrystal would permit the illumination to pass through one pixel at atime through to a detector. A preferred method, however, for thisinvention is to use range gating as described elsewhere herein.

Other methods of associating a distance to a particular reflectionpoint, of course, can now be performed by those skilled in the artincluding variations of the above ideas using a pixel mixing device(such as described in Schwarte, R. “A New Powerful Sensory Tool inAutomotive Safety Systems Based on PMD-Technology”, S-TEC GmbHProceedings of the AMAA 2000) or variations in pixel illumination andshutter open time to determine distance through comparison of rangegated received reflected light. In the laser scanning cases, the totalpower required from the laser is significantly less than in the areaillumination design. However, the ability to correctly change thedirection of the laser beam in a sufficiently short period of timecomplicates the scanning design. The system can work approximately asfollows: The entire area in front of the instant vehicle, perhaps asmuch as a full 180 degree arc in the horizontal plane can be scanned forobjects using either radar or laser radar. Once one or more objects hadbeen located, the scanning range can be severely limited to basicallycover that particular object and some surrounding space using laserradar. Based on the range to that object, a range gate can be used toeliminate all background and perhaps interference from other objects. Inthis manner, a very clear picture or image of the object of interest canbe obtained as well as its location and, through the use of a neuralnetwork, combination neural network or optical correlation or otherpattern recognition system, the identity of the object can beascertained as to whether it is a sign, a truck, an animal, a person, anautomobile or other object. The identification of the object will permitan estimate to be made of the object's mass and thus the severity of anypotential collision.

Once a pending collision is identified, this information can be madeavailable to the driver and if the driver ceases to heed the warning,control of the vehicle could be taken from him or her by the system. Theactual usurpation of vehicle control, however, is unlikely initiallysince there are many situations on the highway where the potential for acollision cannot be accurately ascertained. Consequently, this systemcan be thought of as an interim solution until all vehicles have theRtZF® system described above.

To use the laser radar in a scanning mode requires some mechanism forchanging the direction of the emitted pulses of light. Oneacoustic-optic method of using an ultrasonic wave to change thediffraction angle of a Tellurium dioxide crystal is disclosed elsewhereherein. This can also be done in a variety of other ways such as throughthe use of a spinning multifaceted mirror, such as is common with laserscanners and printers. This mirror would control the horizontalscanning, for example, with the vertical scanning controlled though astepping motor or the angles of the different facets of the mirror canbe different to slightly alter the direction of the scan, or by othermethods known in the art. Alternately, one or more piezoelectricmaterials can be used to cause the laser radar transmitter to rotateabout a pivot point. A rotating laser system, such as described in Shawis the least desirable of the available methods due to the difficulty inobtaining a good electrical connection between the laser and the vehiclewhile the laser is spinning at a very high angular velocity. Anotherpromising technology is to use MEMS mirrors to deflect the laser beam inone or two dimensions. A newer product is the Digital Light Processor(DLP) from Texas Instruments which contains up to several million MEMSmirrors which can be rotated through an angle of up to 12 degrees.Although intended for displays, this device can be used to control thedirection(s) of beams from a laser illuminator. The plus or minus 12degree limitation can be expanded through optics but in itself, it isprobably sufficient. See US published patent application No. 20050278098for more details.

Although the system described above is intended for collision avoidanceor at least the notification of a potential collision, when the roadwayis populated by vehicles having the RtZF® system and vehicles which donot, its use is still desirable after all vehicles are properlyequipped. It can be used to search for animals or other objects whichmay be on or crossing the highway, a box dropping off of a truck forexample, a person crossing the road who is not paying attention totraffic. Motorcycles, bicycles, and other non-RtZF® equipped vehiclescan also be monitored.

One significant problem with all previous collision avoidance systemswhich use radar or laser radar systems to predict impacts with vehicles,is the inability to know whether the vehicle that is being interrogatedis located on the highway or is off the road. In at least one system ofthe present invention, the location of the road at any distance ahead ofthe vehicle would be known precisely from the sub-meter accuracy maps,so that the scanning system can ignore, for example, all vehicles onlanes where there is a physical barrier separating the lanes from thelane on which the subject vehicle is traveling. This, of course, is acommon situation on super highways. Similarly, a parked vehicle on theside of the road would not be confused with a stopped vehicle that is inthe lane of travel of the subject vehicle when the road is curving. Thispermits the subject invention to be used for automatic cruise control.In contrast with radar systems, it does not require that vehicles in thepath of the subject vehicle be moving, so that high speed impacts intostalled traffic can be avoided.

If a system with a broader beam to illuminate a larger area on the roadin front of the subject vehicle is used, with the subsequent focusing ofthis image onto a CCD or CMOS array, this has an advantage of permittinga comparison of the passive infrared signal and the reflection of thelaser radar active infrared. Metal objects, for example appear cold topassive infrared. This permits another parameter to be used todifferentiate metallic objects from non-metallic objects such as foliageor animals such as deer. The breadth of the beam can be controlled andthereby a particular object can be accurately illuminated. With thissystem, the speed with which the beam steering is accomplished can bemuch slower. Both systems can be combined into the maximum amount ofinformation to be available to the system.

Through the use of range gating, objects can be relatively isolated fromthe environment surrounding it other than for the section of highwaywhich is at the same distance. For many cases, a properly trained neuralnetwork or other pattern recognition system can use this data andidentify the objects. An alternate approach is to use the Fouriertransform of the scene as input to the neural network or other patternrecognition system. The advantages of this latter approach are that theparticular location of the vehicle in the image is not critical foridentification. Note that the Fourier transform can be accomplishedoptically and optically compared with stored transforms using a garnetcrystal or garnet films, for example, as disclosed in U.S. Pat. No.5,473,466.

At such time, when the system can take control of the vehicle, it willbe possible to have much higher speed travel. In such cases all vehicleson the controlled roadway will need to have the RtZF® or similar systemas described above. Fourier transforms of the objects of interest can bedone optically though the use of a diffraction system. The Fouriertransform of the scene can then be compared with the library of theFourier transforms of all potential objects and, through a system usedin military target recognition, multiple objects can be recognized andthe system then focused onto one object at a time to determine thedegree of threat that it poses.

Of particular importance is the use of a high powered eye-safe laserradar such as a 30 to 100 watt laser diode in an expanded beam form topenetrate fog, rain and snow through the use of range gating. If aseveral centimeter diameter beam is projected from the vehicle in theform of pulses of from 1 to 10 nanoseconds long, for example, and thereflected radiation is blocked except that from the region of interest,an image can still be captured even though it cannot be seen by thehuman eye. This technique significantly expands the interrogation rangeof the system and, when coupled with the other imaging advantages oflaser radar, offers a competitive system to radar and may in fact renderthe automotive use or radar unnecessary. One method is to use thetechniques described in the patents to 3DV listed above. In one case,for example, if the vehicle wishes to interrogate an area 250 feetahead, a 10 nanosecond square wave signal can be used to control theshutter which is used both for transmission and reception and where theoff period can be 480 nanoseconds. This can be repeated until sufficientenergy has been accumulated to provide for a good image. In thisconnection, a high dynamic range camera may be used such as thatmanufactured by IMS chips of Stuttgart, Germany as mentioned above. Sucha camera is now available with a dynamic range of 160 db. According toIMS, the imager can be doped to significantly increase its sensitivityto IR.

These advantages are also enhanced when the laser radar system describedherein is used along with the other features of the RtZF® system such asaccurate maps and accurate location determination. The forward-lookinglaser radar system can thus concentrate its attention to the knownposition of the roadway ahead rather than on areas where there can be nohazardous obstacles or threatening vehicles.

5.3 Blind Spot Detection

The RtZF® system of this invention also can eliminate the need for blindspot detectors such as discussed in U.S. Pat. No. 5,530,447.Alternately, if a subset of the complete RtZF® system is implemented, asis expected in the initial period, the RtZF® system can be madecompatible with the blind spot detector described in the '447 patent.

One preferred implementation for blind spot monitoring as well as formonitoring other areas near the vehicle is the use of range-gated laserradar using a high power laser diode and appropriate optics to expandthe laser beam to the point where the transmitted infrared energy persquare millimeter is below eye safety limits. Such a system is describedabove

5.4 Anticipatory Sensing—Smart Airbags, Evolution of the System

A key to anticipating accidents is to be able to recognize andcategorize objects that are about to impact a vehicle as well as theirrelative velocity. As set forth herein and in the current assignee'spatents and patent applications, this can best be done using a patternrecognition system such as a neural network, combination neural network,optical correlation system, sensor fusion and related technologies. Thedata for such a neural network can be derived from a camera image butsuch an image can be overwhelmed by reflected light from the sun. Infact, lighting variations in general plague camera-based imagesresulting in false classifications or even no classification.Additionally, camera-based systems are defeated by poor visibilityconditions and, additionally, have interference problems when multiplevehicles have the same system which may require a synchronization takingtime away from the critical anticipatory sensing function.

To solve these problems, imaging systems based on millimeter wave radar,laser radar (lidar) and more recently terahertz radar can be used. Allthree systems generally work for anticipatory sensors since the objectsare near the vehicle where even infrared scanning laser radar in anon-range gated mode has sufficient range in fog. Millimeter wave radaris expensive and to obtain precise images a narrow beam is requiredresulting in large scanning antennas. Laser radar systems are lessexpensive and since the beams are formed using optic technology they aresmaller and easier to manipulate.

When computational power is limited, it is desirable to determine theminimum number of pixels that are required to identify an approachingobject with sufficient accuracy to make the decision to take evasiveaction or to deploy a passive restraint such as an airbag. In onemilitary study for anti-tank missiles, it was found that a total of 25pixels are all that is required to identify a tank on a battlefield. Foroptical occupant detection within a vehicle, thousands of pixels aretypically used. Experiments indicate that by limiting the number ofhorizontal scans to three to five, with on the order of 100 to 300pixels per scan that sufficient information is available to find anobject near to the vehicle and in most cases to identify the object.Once the object has been located then the scan can be confined to theposition of the object and the number of pixels available for analysissubstantially increases. There are obviously many algorithms that can bedeveloped and applied to this problem and it is therefore left to thoseskilled in the art. At least one invention is based on the fact that areasonable number of pixels can be obtained from the reflections ofelectromagnetic energy from an object to render each of the proposedsystems practical for locating, identifying and determining the relativevelocity of an object in the vicinity of a vehicle that poses a threatto impact the vehicle so that evasive action can be taken or a passiverestraint deployed. See the discussion in section 5.5 below for apreferred implementation.

The RtZF® system is also capable of enhancing other vehicle safetysystems. In particular, by knowing the location and velocity of othervehicles, for those cases where an accident cannot be avoided, the RtZF®system will in general be able to anticipate a crash and assessment thecrash severity using, for example, neural network technology. Even witha limited implementation of the RtZF® system, a significant improvementin smart airbag technology results when used in conjunction with acollision avoidance system such as described in Shaw (U.S. Pat. Nos.5,314,037 and 5,529,138) and a neural network anticipatory sensingalgorithm such as disclosed in U.S. Pat. No. 6,343,810. A furtherenhancement would be to code a vehicle-to-vehicle communication signalfrom RtZF® system-equipped vehicles with information that includes thesize and approximate weight of the vehicle. Then, if an accident isinevitable, the severity can also be accurately anticipated and thesmart airbag tailored to the pending event. Information on the type,size and mass of a vehicle can also be implemented as an RFID tag andmade part of the license plate. The type can indicate a vehicle havingprivileges such as an ambulance, fire truck or police vehicle.

Recent developments by Mobileye (www.mobileye.com) describe a method forobtaining the distance to an object and thus the relative velocity.Although this technique has many limitations, it may be useful in someimplementations of one or more of the current inventions.

A further recent development is reported in U.S. patent applicationpublication No. 20030154010, as well as other patents and patentpublications assigned to Ford Global Technologies including 06452535,06480144, 06498972, 06650983, 06568754, 06628227, 06650984, 06728617,06757611, 06775605, 06801843, 06819991, 20030060980, 20030060956,20030100982, 20030154011, 20040019420, 20040093141, 20040107033,20040111200, and 20040117091. In the disclosures herein, emphasis hasbeen placed on identifying a potentially threatening object and onceidentified, the properties of the object such as its size and mass canbe determined. An inferior system can be developed as described in U.S.patent application publication No. 20030154010 where only the size isdetermined. In inventions described herein, the size is inherentlydetermined during the process of imaging the object and identifying it.Also, the Ford patent publications mention the combined use of a radaror a lidar and a camera system. Combined use of radar and a camera isanticipated herein and disclosed in the current assignee's patents.

Another recent development by the U.S. Air Force uses a high poweredinfrared laser operating at wavelengths greater than 1.5 microns and afocal plane array as is reported in “Three-Dimensional Imaging” in AFRLTechnology Horizons, April 2004. Such a system is probably too expensiveat this time for automotive applications. This development illustratesthe fact that it is not necessary to limit the lidar to the nearinfrared part of the spectrum and in fact, the further that thewavelength is away from the visible spectrum, the higher the powerpermitted to be transmitted. Also, nothing prevents the use of multiplefrequencies as another method of providing isolation from transmissionsfrom vehicles in the vicinity. As mentioned above for timingtransmissions, the GPS system can also be used to control the frequencyof transmission thus using frequency as a method to preventinterference. The use of polarizing filters to transmit polarizedinfrared is another method to provide isolation between differentvehicles with the same or similar systems. The polarization angle can bea function of the GPS location of the vehicle.

It is an express intention of some of the inventions herein to provide asystem that can be used both in daytime and at night. Other systems areintended solely for night vision such as those disclosed in U.S. Pat.No. 6,730,913, U.S. Pat. No. 6,690,017 and U.S. Pat. No. 6,725,139. Notethat the use of the direction of travel as a method of determining whento transmit infrared radiation, as disclosed in these and other FordGlobal patents and patent applications, can be useful but it fails tosolve the problem of the transmissions from two vehicles traveling inthe same vicinity and direction from receiving reflections from eachothers' transmissions. If the directional approach is used, then someother method is required such as coding the pulses, for example.

U.S. Pat. No. 6,730,913 and U.S. Pat. No. 6,774,367 are representativeof a series of patents awarded to Ford Global Technologies as discussedabove. These patents describe range gating as disclosed in the currentassignee's earlier patents. An intent is to supplement the headlightswith a night vision system for illuminating objects on the roadway inthe path of the vehicle but are not seen by the driver and displayingthese objects in a heads-up display. No attempt is made to locate theeyes of the driver and therefore the display cannot place the objectswhere they would normally be located in the driver's field of view asdisclosed in the current assignee's patents. Experiments have shown thatwithout this feature, a night vision system is of little value and mayeven distract the driver to where his or her ability to operate themotor vehicle is degraded. Other differences in the '913 and '367 systeminclude an attempt to compensate for falloff in illumination due todistance, neglecting a similar and potentially more serious falloff dueto scattering due to fog etc. In at least one of the inventionsdisclosed herein, no attempt is made to achieve this compensation in asystematic manner but rather the exposure is adjusted so that asufficiently bright image is achieved to permit object identificationregardless of the cause of the attenuation. Furthermore, in at least oneembodiment, a high dynamic range camera is used which automaticallycompensates for much of the attenuation and thus permits the minimumexposure requirements for achieving an adequate image. In at least oneof the inventions disclosed herein, the system is used both at night andin the daytime for locating and identifying objects and, in some cases,initiating an alarm or even taking control of the vehicle to avoidaccidents. None of these objects are disclosed in the '913 or '367patents and related patents. Additionally, US20030155513, also part ofthis series of Ford Global patents and applications, describesincreasing the illumination intensity based on distance to the desiredfield of view. In at least one of the inventions disclosed herein, theillumination intensity is limited by eye safety considerations ratherthan distance to the object of interest. If sufficient illumination isnot available on one pulse, additional pulses are provided untilsufficient illumination to achieve an adequate exposure is achieved.

If the laser beam diverges, then the amount of radiation per squarecentimeter illuminating a surface will be a function of the distance ofthat surface from the transmitter. If that distance can be measured,then the transmitted power can be increased while keeping the radiationper square centimeter below the eye safe limits. Using this technique,the amount of radiated power can be greatly increased thus enhancing therange of the system in daylight and in bad weather. A lower power pulsewould precede a high power pulse transmitted in a given direction andthe distance measured to a reflective object would be measured and thetransmitted power adjusted appropriately. If a human begins to intersectthe path of transmission, the distance to the human would be measuredbefore he or she could put his or her eye into the transmission path andthe power can be reduced to remain within the safety standards.

It is also important to point out that the inventions disclosed hereinthat use lidar (laser radar or ladar) can be used in a scanning modewhen the area to be covered is larger that the beam diameter or in apointing mode when the beam diameter is sufficient to illuminate thetarget of interest, or a combination thereof.

It can be seen from the above discussion that the RtZF® system willevolve to solve many safety, vehicle control and ITS problems. Even suchtechnologies as steering and drive by wire will be enhanced by the RtZF®system in accordance with invention since it will automatically adjustfor failures in these systems and prevent accidents.

5.5 A Preferred Implementation

FIGS. 21A and 21B illustrate a preferred embodiment of a laser radarsystem having components mounted at the four corners of a vehicle abovethe headlights and tail lights. Laser radar units or assemblies 260 and261 have a scan angle of approximately 150 degrees; however, for someapplications a larger or smaller scanning angle can of course be used.The divergence angle for the beam for one application can be one degreeor less when it is desired to illuminate an object at a considerabledistance from the vehicle such as from less than fifty meters to 200meters or more. In other cases, where objects are to be illuminated thatare closer to the vehicle, a larger divergence angle can be used.Generally, it is desirable to have a field of illumination (FOI)approximately equal to the field of view (FOV) of the camera or otheroptical receiver. FIGS. 22A and 22B illustrate the system of FIGS. 21Aand 21B for vehicles on a roadway. Note that the divergence angle in thehorizontal plane and vertical plane are not necessarily equal.

FIGS. 23A and 23B illustrate an alternative mounting location for laserradar units on or near the roof of a vehicle. They can be either insideor outside of the vehicle compartment. The particular design of thelaser radar assemblies 262 and 263 are similar to those used in FIGS.21A, 21B, 22A and 22B. Although not shown, other geometries are ofcourse possible such as having the laser radar assemblies mounted on ornear the roof for the rear assemblies and above the headlights for thefrontal assemblies or vice versa. Also, although assemblies mounted onthe corners of the vehicle are illustrated, in some cases it may bedesirable to mount laser radar assemblies in the center of the front,back and sides of the vehicle or a combination or center andcorner-mounted laser radar assemblies can be used.

FIG. 24 is a schematic illustration of a typical laser radar assemblyshowing the scanning or pointing system with simplified optics forillustration only. In an actual design, the optics will typicallyinclude multiple lenses. Also, the focal point will typically not beoutside of the laser radar assembly. In this non-limiting example, acommon optical system 267 is used to control a laser light 265 and animager or camera 266. The laser source transmits, usually eye-safeinfrared, light through its optical sub-system 271 which collimates theradiation. The collimated radiation is then reflected off mirror 273 tomirror 274 which reflects the radiation to the desired direction throughlens system 267. The direction of the beam can be controlled by a motor272 which can rotate both mirror 274 and optical system 267 to achievethe desired scanning or pointing angle for scanning designs. A preferredapproach is to use a non-scanning approach. The radiation leaves theoptical system 267 and illuminates the desired object or target 276. Theradiation reflected from object 276 can pass back through lens 267,reflect off mirror 274 pass through semitransparent mirror 273 throughoptic subsystem 268 and onto optical sensitive surface 266. Many otherconfigurations are possible. The transmission of the radiation iscontrolled by optical shutter 270 via controller 275. Similarly, thelight that reaches the imager 266 is controlled by controller 275 andoptical shutter 269. These optical shutters 269, 270 can be liquidcrystal devices, Kerr or Pockel cells, garnet films, other spatial lightmonitors or, preferably, high speed optical shutters such as describedin patents and patent applications of the 3DV Systems Ltd., of Yokneam,Israel, as set forth above or equivalent. Since much of the technologyused in this invention related to the camera and shutter system isdisclosed in the 3DV patents and patent applications, it will not berepeated here, by is incorporated by reference herein.

In some embodiments, it may be important to assure that the lens throughwhich the laser radar radiation passes is clean. As a minimum, adiagnostic system is required to inform the RtZF® or other system thatthe lens are soiled and therefore the laser radar system can not berelied upon. Additionally, in some applications, means are provided toclean one or more of the lens or to remove the soiled surface. In thelatter case, a roll of thin film can be provided which, upon thedetection of a spoiled lens, rolls up a portion of the film and therebyprovides a new clean surface. When the roll is used up it can bereplaced. Other systems provide one or more cleaning methods such as asmall wiper or the laser radar unit can move the lens into a cleaningstation. Many other methods are of course possible and the inventionhere is basically concerned with ascertaining that the lens is clean andif not informing the system of this fact and, in some cases, cleaning orremoving the soiled surface. The lens can also be coated with a coatingthat resists soiling as disclosed in U.S. Pat. No. 7,136,494, ZUS6991339and U.S. Pat. No. 6,193,378.

Note that although laser radar and radar have been discussed separately,in some implementations, it is desirable to use both a radar system anda laser radar system. Such a case can be where the laser radar system isnot capable to achieve sufficient range in adverse weather whereas theradar has the requisite range but insufficient resolution. The radarunit can provide a warning that a potentially dangerous situation existsand thus the vehicle speed should be reduced until the laser radardevice and obtain an image with sufficient resolution to permit anassessment of the extent of the danger and determine whether appropriateactions should be undertaken.

5.6 Antennas

When the interrogation system makes use of radar such as systems in useat 24 GHz and 77 GHz, a key design issue is the antenna. The inventionsherein contemplate the use of various types of antennas such as dipoleand monopole designs, yagi, steerable designs such as solid state phasedarray and so called smart antennas. All combinations of antennas forradar surveillance around a vehicle are within the scope if theinventions disclosed herein. In particular, the Rotman lens offerssignificant advantages as disclosed in L. Hall, H. Hansen and D. Abbott“Rotman lens for mm-wavelengths”, Smart Structures, Devices, andSystems, SPIE Vol. 4935 (2002). Other antenna designs can be applicable.In some cases, one radar source can be used with multiple antennas.

6. Smart Highways

A theme of inventions disclosed herein is that automobile accidents canbe eliminated and congestion substantially mitigated through theimplementation of these disclosed inventions. After sufficientimplementations have occurred, the concept of a smart highway becomesfeasible. When a significant number of vehicles have the capability ofoperating in a semi-autonomous manner, then dedicated highway lanes(like the HOV lanes now in use) can be established where use of thelanes is restricted to properly equipped vehicles. Vehicles operating inthese lanes can travel in close-packed, high speed formations since eachof them will know the location of the road, their location on the roadand the location of every other vehicle in such a lane. Accidents inthese lanes will not occur and the maximum utilization of the roadwayinfrastructure will have been obtained. Vehicle owners will be highlymotivated to own equipped vehicles since their travel times will besignificantly reduced and while traveling in such lanes, control of thevehicle can be accomplished by the system and they are then free to talkon the telephone, read or whatever.

7. Weather and Road Condition Monitoring

The monitoring of the weather conditions and the control of the vehicleconsistent with those conditions has been discussed herein. Themonitoring of the road conditions and in particular icing has also beendiscussed elsewhere herein and in other patents and patent applicationsof the current assignee. Briefly, a vehicle will be controlled so as toeliminate accidents under all weather and road conditions. This in somecases will mean that the vehicle velocity will be controlled and, insome cases, travel will be prohibited until conditions improve.

8. Communication with Other Vehicles—Collision Avoidance

8.1 Requirements

MIR might also be used for vehicle-to-vehicle communication except thatit is line of sight. An advantage is that we can know when a particularvehicle will respond by range gating. Also, the short time oftransmission permits many vehicles to communicate at the same time. Apreferred system is to use spread spectrum carrier-less coded channels.

One problem which will require addressing as the system becomes matureis temporary blockage of a satellite by large trucks or other movableobjects whose location cannot be foreseen by the system designers.Another concern is to prevent vehicle owners from placing items on thevehicle exterior that block the GPS and communication antennas.

The first problem can be resolved if the host vehicle can communicatewith the blocking trucks and can also determine its relative location,perhaps through using the vehicle exterior monitoring system. Then thecommunication link will provide the location of the adjacent truck andthe monitoring system will provide the relative location and thus theabsolute location of the host vehicle can be determined.

The communication between vehicles for collision avoidance purposescannot solely be based on line-of-sight technologies as this is notsufficient since vehicles which are out of sight can still causeaccidents. On the other hand, vehicles that are a mile away from oneanother but still in sight, need not be part of the communication systemfor collision avoidance purposes. Messages sent by each vehicle, inaccordance with an embodiment of the invention, can contain informationindicating exactly where it is located and perhaps information as towhat type of vehicle it is. The type of vehicle can include emergencyvehicles, construction vehicles, trucks classified by size and weight,automobiles, and oversized vehicles. The subject vehicle can thereforeeliminate all vehicles that are not potential threats, even if suchvehicles are very close, but on the other side of the highway barrier.

The use of a wireless Ethernet protocol can satisfy the needs of thenetwork, consisting of all threatening vehicles in the vicinity of thesubject vehicle. Alternately, a network where the subject vehicletransmits a message to a particular vehicle and waits for a responsecould be used. From the response time, assuming that the clocks of bothvehicles are or can be synchronized, the relative position of othervehicles can be ascertained which provides one more method of positiondetermination. Thus, the more vehicles that are on the road with theequipped system, the greater accuracy of the overall system and thesafer the system becomes.

To prevent accidents caused by a vehicle leaving the road surface andimpacting a roadside obstacle requires only an accurate knowledge of theposition of the vehicle and the road boundaries. To prevent collisionswith other vehicles requires that the position of all nearby automobilesideally should be updated continuously. However, just knowing theposition of a threatening vehicle is insufficient. The velocity, sizeand/or orientation of the vehicle are also important in determining whatdefensive action or reaction may be required. Once all vehicles areequipped with the system of this invention, the communication of allrelevant information will take place via a communication link, e.g., aradio link. In addition to signaling its absolute position, each vehiclewill send a message identifying the approximate mass, velocity,orientation and/or other relevant information. This has the addedbenefit that emergency vehicles can make themselves known to allvehicles in their vicinity and all such vehicles can then takeappropriate action to allow passage of the emergency vehicle. The samesystem can also be used to relay accident or other hazard informationfrom vehicle-to-vehicle through an ad-hoc or mesh network.

8.2 A Preferred System

One preferred method of communication between vehicles uses that portionof the electromagnetic spectrum that permits only line of sightcommunication. In this manner, only those vehicles that are in view cancommunicate. In most cases, a collision can only occur between vehiclesthat can see each other. This system has the advantage that the“communications network” only contains nearby vehicles. This wouldrequire that when a truck, for example, blocks another stalled vehiclethat the information from the stalled vehicle be transmitted via thetruck to a following vehicle. An improvement in this system would use arotating aperture that would only allow communication from a limitedangle at a time further reducing the chance for multiple messages tointerfere with each other. Each vehicle transmits at all angles butreceives at only one angle at a time. This has the additional advantageof confirming at least the direction of the transmitting vehicle. Aninfrared rotating receiver can be looked at as similar to the human eye.That is, it is sensitive to radiation from a range of directions andthen focuses in on the particular direction, one at a time, from whichthe radiation is coming. It does not have to scan continuously. In fact,the same transmitter which transmits 360 degrees could also receive from360 degrees with the scanning accomplished using software.

An alternate preferred method is to use short distance radiocommunication so that a vehicle can receive position information fromall nearby vehicles such as the DS/SS system. The location informationreceived from each vehicle can then be used to eliminate it from furthermonitoring if it is found to be on a different roadway or not in apotential path of the subject vehicle.

Many communications schemes have been proposed for inter-vehicle andvehicle-to-road communication. At this time, a suggested approachutilizes DS/SS communications in the 2.4 GHz INS band. Experiments haveshown that communications are 100 percent accurate at distances up to200 meters. At a closing velocity of 200 KPH, at 0.5 g deceleration, itrequires 30 meters for a vehicle to stop. Thus, communications accurateto 200 meters is sufficient to cover all vehicles that are threateningto a particular vehicle.

A related method would be to use a MIR system in a communications mode.Since the width of the pulses typically used by MIR is less than ananosecond, many vehicles can transmit simultaneously without fear ofinterference. Other spread spectrum methods based on ultra wideband ornoise radar are also applicable. In particular, as discussed below, acommunication system based on correlation of pseudorandom or other codesis preferred.

With either system, other than the MIR system, the potential exists thatmore than one vehicle will attempt to send a communication at the sametime and there will then be a ‘data collision’. If all of thecommunicating vehicles are considered as being part of a local areanetwork, the standard Ethernet protocol can be used to solve thisproblem. In that protocol, when a data collision occurs, each of thetransmitting vehicles which was transmitting at the time of the datacollision would be notified that a data collision had occurred and thatthey should retransmit their message at a random time later. Whenseveral vehicles are in the vicinity and there is the possibility ofcollisions of the data, each vehicle can retain the coordinates lastreceived from the surrounding vehicles as well as their velocities andpredict their new locations even though some data was lost.

If a line of sight system is used, an infrared, terahertz or MIR systemwould be good choices. In the infrared case, and if an infrared systemwere also used to interrogate the environment for non-equipped vehicles,pedestrians, animals etc., as discussed below, both systems could usesome of the same hardware.

If point-to-point communication can be established between vehicles,such as described in U.S. Pat. No. 5,528,391 to Elrod, then the need fora collision detection system like Ethernet would not be required. If thereceiver on a vehicle, for example, only has to listen to one senderfrom one other vehicle at a time, then the bandwidth can be considerablyhigher since there will not be any interruption.

When two vehicles are communicating their positions to each other, it ispossible through the use of range gating or the sending of a “clear tosend signal” and timing the response to determine the separation of thevehicles. This assumes that the properties of the path between thevehicles are known which would be the case if the vehicles are withinview of each other. If, on the other hand, there is a row of trees, forexample, between the two vehicles, a false distance measurement would beobtained if the radio waves pass through a tree. If the communicationfrequency is low enough that it can pass through a tree in the aboveexample, it will be delayed. If it is a much higher frequency such thatis blocked by the tree, then it still might reach the second vehiclethrough a multi-path. Thus, in both cases, an undetectable range errorresults. If a range of frequencies is sent, as in a spread spectrumpulse, and the first arriving pulse contains all of the sentfrequencies, then it is likely that the two vehicles are in view of eachother and the range calculation is accurate. If any of the frequenciesare delayed, then the range calculation can be considered inaccurate andshould be ignored. Once again, for range purposes, the results of manytransmissions and receptions can be used to improve the separationdistance accuracy calculation. Alternate methods for determining rangecan make use of radar reflections, RFID tags etc.

8.3 Enhancements

In an accident avoidance system of the present invention, theinformation indicative of a collision could come from a vehicle that isquite far away from the closest vehicles to the subject vehicle. This isa substantial improvement over the prior art collision avoidancesystems, which can only react to a few vehicles in the immediatevicinity. The system described herein also permits better simultaneoustracking of several vehicles. For example, if there is a pileup ofvehicles down the highway, then this information can be transmitted tocontrol other vehicles that are still a significant distance from theaccident. This case cannot be handled by prior art systems. Thus, thesystem described here has the potential to be used with the system ofthe U.S. Pat. No. 5,572,428 to Ishida, for example.

The network analogy can be extended if each vehicle receives andretransmits all received data as a single block of data. In this way,each vehicle is assured in getting all of the relevant information evenif it gets it from many sources. Even with many vehicles, the amount ofdata being transmitted is small relative to the bandwidth of theinfrared optical or radio technologies. In some cases, a receiver andre-transmitter can be part of the highway infrastructure. Such a casemight be on a hairpin curve in the mountains where the oncoming trafficis not visible.

In some cases, it may be necessary for one vehicle to communicate withanother to determine which evasive action each should take. This couldoccur in a multiple vehicle situation when one car has gone out ofcontrol due to a tire failure, for example. In such cases, one vehiclemay have to tell the other vehicle what evasive actions it is planning.The other vehicle can then calculate whether it can avoid a collisionbased on the planned evasive action of the first vehicle and if not, itcan inform the first vehicle that it must change its evasive plans. Theother vehicle would also inform the first vehicle as to what evasiveaction it is planning. Several vehicles communicating in this manner candetermine the best paths for all vehicles to take to minimize the dangerto all vehicles.

If a vehicle is stuck in a corridor and wishes to change lanes in heavytraffic, the operator's intention can be signaled by the operatoractivating the turn signal. This could send a message to other vehiclesto slow down and let the signaling vehicle change lanes. This would beparticularly helpful in an alternate merge situation and have asignificant congestion reduction effect. A signal can also be sent whenthe driver panic-brakes or has an accident.

8.4 Position-Based Code Communication

In conventional wireless communication such as between cell phones and acell phone station or computers in a local area network, a limitednumber of clients are provided dedicated channels of communication witha central server. The number of channels is generally limited and thedata transfer rate is maximized. The situation of communication betweenvehicles (cars, trucks, buses, boats, ships, airplanes) is different inthat devices are all peers and the communication generally depends ontheir proximity. In general, there is no central server and each vehiclemust be able to communicate with each other vehicle without goingthrough a standard server.

Another distinguishing feature is that there may be a large number ofvehicles that can potentially communicate with a particular vehicle.Thus, there needs to be a large number of potential channels ofcommunication. One method of accomplishing this is based on the conceptof noise radar as developed by Lukin et al. and described in thefollowing:

1. K. A. Lukin. Noise Radar Technology for Short Range Applications,Proc of the 5th Int. Conference and Exhibition on Radar Systems, (RADAR'99), May 17-21, Brest, France, 1999, 6 pages;

2. K. A. Lukin. Advanced Noise Radar Technology. Proc. of the PIERSWorkshop on Advances in Radar Methods. Apr. 20-22, 1998, Hotel Dino,Baveno, Italy, JRC-Ispra 1998, pp. 137-140;

3. W. Keydel and K. Lukin. Summary of Discussion in working Group V:Unconventional New Techniques and Technologies for Future Radar, Proc.of the PIERS Workshop in Radar Methods. Apr. 20-22, 1998, Hotel Dino,Baveno, Italy, 1998, pp. 28-30;

4. Lukin K. A., Hilda A. Cerdeira and Colavita A. A. Chaotic instabilityof currents in reverse biased multilayered structure. Appl. PhysicsLetter, v. 77(17), 27 Oct. 1997, pp. 2484-2496;

5. K. A. Lukin. Noise Radar Technology for Civil Application. Proc. ofthe 1st EMSL User Workshop. 23-24 Apr. 1996, JRC-Ispra, Italy, 1997, pp.105-112;

6. A. A. Mogyla. Adaptive signal filtration based on the two-parametricrepresentation of random processes. Collective Volume of IRE NASU, Vol.2, No. 2 pp. 137-141, 1997, (in Russian);

7. A. A. Mogyla, K. A. Lukin. Two-Parameter Representation ofNon-Stationary Random Signals with a Finite Weighted Average Value ofEnergy. The Collective Volume of IRE NASU, No. 1, pp. 118-124, 1996, (inRussian);

8. K. A. Lukin. Noise Radar with Correlation Receiver as the Basis ofCar Collision Avoidance System. 25th European Microwave Conference,Bologna; Conference Proceedings, UK, Nexus, 1995, pp. 506-507, 1995;

9. K. A. Lukin, V. A. Rakityansky. Dynamic chaos in microwaveoscillators and its applications for Noise Radar development, Proc. 3rdExperimental Chaos Conference, Edinburg, Scotland, UK, 21-23 August,1995;

10. V. A. Rakityansky, K. A. Lukin. Excitation of the chaoticoscillations in millimeter BWO, International Journal of Infrared andMillimeter Waves, vol. 16, No. 6, June, pp. 1037-1050, 1995;

11. K. A. Lukin. Ka-band Noise Radar. Proc. of the Millimeter andSubmillimeter Waves, Jun. 7-10, 1994, Kharkov, Ukraine; Vol. 2, pp.322-324, 1994;

12. K. A. Lukin, Y. A. Alexandrov, V. V. Kulik, A. A. Mogila, V. A.Rakityansky. Broadband millimeter noise radar, Proc. Int. Conf. onModern Radars, Kiev, Ukraine, pp. 30-31, 1994 (in Russian);

13. K. A. Lukin. High-frequency chaotic oscillations from Chua'scircuit. Journal of Circuits, Systems, and Computers, Vol. 3, No. 2,June 1993, pp. 627-643; In the book: Chua's Circuit Paradigma for Chaos,World Scientific, Singapore, 1993;

14. K. A. Lukin, V. A. Rakityansky. Application of BWO for excitation ofthe intensive chaotic oscillations of millimeter wave band. 23-rdEuropean Microwave Conference. Sep. 6-9, Madrid, Spain. Conf. Proceed.pp. 798-799, 1993;

15. K. A. Lukin, V. A. Rakityansky. Excitation of intensive chaoticoscillations of millimetre wave band. Proc. of ISSSE, Paris, Sep. 1-4,pp. 454-457, 1992;

16. V. V. Kulik, K. A. Lukin, V. A. Rakityansky. Non-CoherentReflectometry Method for Measurement of Plasma Cut-Off Layer Position,Proc. of the Int. Conference on Millimeter Wave and Far-Infrared.Technology, Beijing, China, 17-21 August, 1992;

17. V. V. Kulik, K. A. Lukin, V. A. Rakityansky. Autodyne effect in BWOwith chaotic dynamic. Collective Volume of IRE NASU, pp. 95-100, 1992,(in Russian);

18. V. V. Kulik, K. A. Lukin, V. A. Rakityansky. Application ofnoncoherent reflectometry method for fusion plasma dyagnostic.Collective Volume of IRE NASU, pp. 13-18, 1992, (in Russian);

19. B. P. Efimov, K. A. Lukin, V. A. Rakityansky. Chaotic interaction ofmodes in the electron-wave auto-oscillator with two feedback channels,Letters in Journal of Technical Physics, v. 15, No. 18, pp. 9-12, 1989,(in Russian);

20. B. P. Efimov, K. A. Lukin, V. A. Rakityansky. Transformation ofchaotic oscillation power spectrum by reflections. Journal of TechnicalPhysics, vol. 58, No. 12, pp. 2388-2400, 1988 (in Russian)).

The concept of noise radar is discussed in the Lukin references listedabove. A description of noise radar is included elsewhere herein and thediscussion here will be limited to the use of pseudo random noise in aspread spectrum or Ultra-wideband spectrum environment for communicationpurposes. The principles disclosed, however, are applicable to othercommunication protocols and not limited to UWB, MIR or other spreadspectrum based systems. In many ways and for many purposes, UWB and MIRcan be considered equivalent.

Generally, a particular segment or band of the electromagnetic spectrumwhich is compatible with FCC regulations will be selected forvehicle-to-vehicle communication purposes. Such a band could include,for example 5.9 GHz to 5.91 GHz. The noise communication device willtherefore transmit information in that band or other band permitted bythe FCC. In this example, each vehicle can transmit a pseudorandom noisesignal or pulse in a carrier-less fashion composed of frequencies withinthe chosen band. The particular code transmitted by a particular vehicleshould be unique. Generally, the vehicle will transmit its coderepetitively with a variable or fixed spacing between transmissions. Theinformation which the vehicle wishes to transmit is encoded using thevehicle's code by any of a number of different techniques includingphase modulation of distance or time between code transmissions, phaseor amplitude modulation of the code sequences themselves, changes of thepolarity of the entire code sequence or the individual code segments, orbandwidth modulation of the code sequence. Other coding technologieswould also applicable and this invention is not limited to anyparticular coding method.

For example, a vehicle can have a 64 bit code which can be a combinationof a vehicle identification number and the GPS coordinates of thevehicle location. The vehicle would continuously transmit this 64 bitcode using frequencies within the selected band. The 64 bit code couldinclude both positive and negative bits in addition to 0 bits. Whenidentifying the vehicle, the receiver could rectify the bits resultingin a 64 bit code of 0's and 1's. The information which the transmittingvehicle wishes to send could be represented by the choice of polarity ofeach of the code bits.

Once a particular vehicle begins communicating with another particularvehicle, the communication channel must remain intact until the entiremessage has been transmitted. Since there may be as many as 100 to 1000vehicles simultaneously transmitting within radio range of the receivingvehicle, a transmitting vehicle must have a code which can be knownbefore hand to the receiving vehicle. One preferred technique is to makethis identification code a function of the GPS coordinate location, or asubset thereof such as the last three or four digits that provide thevehicle position up to the closest 5 meters, for example, oftransmitting vehicle. The code would need to be coarse enough so thatinformation to be transmitted by the transmitting vehicle isaccomplished before the transmitting vehicle changes its identification.If this information includes a position and velocity of the transmittingvehicle, then the receiving vehicle can determine the new transmittingcode of the transmitting vehicle.

For example, the transmitting vehicle determines its location within onemeter. It is unlikely that any other vehicle will be located within thesame meter or even five meters as the transmitting vehicle. Thus, thetransmitting vehicle will have a unique code which it can send as apseudorandom sequence in the noise communication system. A nearbyvehicle can search all information received by its antenna for asequence which represents each space within 30 meters of the receivingvehicle, for example. If it detects such a sequence, it will know thatthere are one or more vehicles within 30 meters of the receivingvehicle. The search can now be refined to locate vehicles based on theirdirection since again the receiving vehicle can calculate the sequencesthat would be transmitted from a vehicle from any particular locationwithin the 30 meter range. Once a particular vehicle has beenidentified, the receiving vehicle can begin to receive information fromthe transmitting vehicle through one or more of the coding schemeslisted above. Since the information will preferably contain at least thevelocity of transmitting vehicle, the receiving vehicle can predict anycode sequence changes that take place and thus maintain communicationwith a particular vehicle even as the vehicle's code changes due to itschanging position. The information being transmitted can also containadditional information about the vehicle and/or its occupants.

In this manner, a receiving vehicle can selectively receive informationfrom any vehicle within its listenable range. Such range may be limitedto 100 meters for a highly congested area or extend to 5000 meters in arural environment. In this manner, each vehicle becomes a node on thetemporary local area network and is only identified by its GPS location.Any vehicle can communicate with any other vehicle and when manyvehicles are present, a priority scheme can be developed based on theurgency of the message, the proximity of vehicle, the possibility of acollision, or other desired prioritizing scheme.

The code transmitted by a particular vehicle can begin with a sequencethat indicates, for example, the largest GPS segment that locates thevehicle which may be a segment 100 km square, for example. The next bitsin the sequence would indicate which of next lower subsections which,for example, could be 10 km square. The next set of bits could furtherrefine this to a 1 km square area and so on down to the particularsquare meter where the vehicle is located. Other units such as angles,degrees, minutes, seconds, or the road being traveled etc., could bemore appropriate for locating a vehicle on the surface of sphericalearth. By using this scheme, a receiving vehicle can search for allvehicles located within its 1 km or square segment and then when avehicle is found, the search can be continuously refined until the exactlocation of the transmitting vehicle has been determined. This can bedone through correlation. The 100 or so vehicles transmitting with arange would all transmit low level signals which would appear as noiseto the receiving vehicle. The receiving vehicle would need to know thecode a particular vehicle was transmitting before it could identifywhether that code was present in the noise. The code derived by thevehicle to be transmitted must be sufficiently unique that only onevehicle can have a particular code at a particular time. Since themessages from different vehicles are separated through correlationfunctions, all vehicles must have unique transmission codes which arenot known beforehand by the receiving vehicle yet must be derivable bythe receiving vehicle. The location digits that comprise the code can belimited to the range that the system can cover. A 100 Km code sequenceis not necessary if the maximum communication range of the system is 10Km, for example. Similarly a 10 cm sequence can also be unnecessary. Acode indicating the road can be important.

The communication need not be limited to communication between movingvehicles. This same technology permits communication between a vehicleand an infrastructure-based station.

There is no limit to the types of information that can be exchangedbetween vehicles or between vehicles and infrastructure-based stations.For example, if an event occurs such as an accident or avalanche, roaderosion, fallen tree, or other event which temporarily changes theability to travel safely on a section of a lane on a highway, anauthorized agent can place the transmitting sign near the affectedsection of roadway which would transmit information using the noisecommunication technique to all oncoming vehicles within a 1 km range,for example. Prior to the placement of such a sign, a police vehiclecould transmit a similar message to adjacent vehicles. Even an ordinarydriver who first appears on the scene and identifies a potential hazardcan send this message to vehicles within range of the hazard and can tagthis message as a high priority message. An infrastructure-basedreceiving station can receive such a message and notify the emergencycrews that attention is immediately required at a particular location onthe highway. In this manner, all vehicles that could be affected by suchan event as well as emergency response organizations can be immediatelynotified as soon as a hazard, such as an accident, occurs therebygreatly reducing the response time and minimizing the chance of vehiclesengaging the hazardous location.

If a vehicle passes through a precise positioning location as describedelsewhere herein, that vehicle (the vehicle's processor or computer)momentarily knows or can calculate the errors in the GPS signals andthus becomes a differential correction station. The error correctionscan then be transmitted to nearby vehicles plus enhancing theirknowledge of their position. If the PPS vehicle also has an onboardaccurate clock, then the carrier phase of the satellite signals at thePPS location can be predicted and thus, as the vehicle leaves the PPSstation, it can operate on carrier phase RTK differential GPS and thusknow its position within centimeters or less. Similarly, if the phase ofthe carrier waves at PPS station is transmitted to adjacent vehicles,each vehicle also can operate on RTK carrier phase differential GPS.Thus, as many cars pass the PPS the accuracy with which each vehicleknows its position is continuously upgraded and at the time when thelikelihood of collision between vehicles is a maximum, that is when manyvehicles are traveling on a roadway, the accuracy with which eachvehicle knows its location is also maximized. The RtZF® systemautomatically improves as the danger of collision increases.

Other information which a vehicle can transmit relates to the GPSsignals that it is receiving. In this manner, another form ofdifferential GPS can occur called relative differential GPS. Withoutnecessarily improving the accuracy with which a given vehicle preciselyknows its position, by comparing GPS signals from one vehicle toanother, the relative location of two vehicles can again be veryaccurately determined within centimeters. This of course is particularlyimportant for collision avoidance.

Other information that can be readily transmitted either from vehicle tovehicle or from infrastructure-based stations to vehicles includes anyrecent map updates. Since a vehicle will generally always be listening,whenever a map update occurs this information can be received by avehicle provided it is within range of a transmitter. This could occurovernight while the vehicle is in the garage, for example, or wheneverthe vehicle is not operating, e.g., parked. Each vehicle would have acharacteristic time indicating the freshness of the information in itslocal map database. As the vehicle travels and communicates with othervehicles, this data can be readily exchanged and if a particular vehiclehas a later map version than the other vehicle, it would signal thefirst vehicle requesting that the differences between the two mapdatabases be transmitted from the first to the second vehicle. Thistransmission can also occur between an infrastructure-based station anda vehicle. Satellites, cell phone towers, etc. can also be used for mapupdating purposes.

If the operator of a particular vehicle wishes to send a text or voicemessage to another identified vehicle, this information can also be sentthrough the vehicle-to-vehicle communication system described herein.Similarly, interaction with the Internet via an infrastructure-basedstation such as WiMAX can also be accomplished. In some cases, it may bedesirable to access the Internet using communication channels with othervehicles. Perhaps, one vehicle has the satellite, Wi-Fi, Wimax or otherlink to the Internet while a second vehicle does not. The second vehiclecould still communicate with the Internet through the firstInternet-enabled vehicle.

Through the communication system based on noise or pseudonoisecommunication as described above is ubiquitous, the number of pathsthrough which information can be transmitted to and from a vehicle issubstantially increased which also greatly increases the reliability ofthe system since multiple failures can occur without affecting theoverall system operation. Thus, once again the goal of zero fatalitiesis approached through this use of vehicle-to-vehicle communication.

By opening this new paradigm for communication between vehicles, andthrough the use of message relay from one vehicle to another, occupantsof one vehicle can communicate with any other vehicle on a road.Similarly, through listening to infrastructure-based stations, theoccupants can communicate with non-vehicle occupants. In many ways, thissystem supplements the cell phone system but is organized under totallydifferent principles. In this case, the communication takes placewithout central stations or servers. Although servers and centralstations can be attached to the system, the fundamental structure is oneof independent nodes and temporary connections based on geographicproximity.

The system is self limiting in that the more vehicles communicating thehigher the noise level and the more difficult it will be to separatemore distant transmitters. When a vehicle is traveling in a ruralenvironment, for example, where there are few sparsely locatedtransmitters, the noise level will be low and communication with moredistant vehicles facilitated. On the other hand, during rush hour, therewill be many vehicles simultaneously communicating thus raising thenoise level and limiting the ability of a receiver to receive distanttransmissions. Thus, the system is automatically adjusting.

There are several collision avoidance-based radar systems beingimplemented on vehicles on the highways today. The prominent systemsinclude ForeWarn™ by Delco division of the Delphi Corporation and theEaton Vorad systems. These systems are acceptable as long as fewvehicles on the roads have such system. As the number of radar-equippedvehicles increases, the reliability of each system decreases as radartransmissions are received that originate from other vehicles. Thisproblem can be solved through the use of noise radar as described in thevarious technical papers by Lukin et al listed above.

Noise radar typically operates in a limited band of frequenciessimilarly to spread spectrum technologies. Whereas spread spectrumutilizes a form of carrier frequency modulation, noise radar does not.It is carrier-less. Typically, a noise-generating device is incorporatedinto the radar transmitter such that the signal transmitted appears asnoise to any receiver. A portion of the noise signal is captured as itis transmitted and fed to a delay line for later use in establishing acorrelation with a reflected pulse. In the manner described in the Lukinet al. papers, the distance and velocity of a reflecting object relativeto the transmitter can be readily determined and yet be detectable byany other receiver. Thus, a noise radar collision avoidance system suchas discussed in U.S. Pat. No. 6,121,915, U.S. Pat. No. 5,291,202, U.S.Pat. No. 5,719,579, and U.S. Pat. No. 5,075,863 becomes feasible. Lukinet al. first disclosed this technology in the above-referenced papers.

Although noise radar itself is not new, the utilization of noise radarfor the precise positioning system described herein is not believed tohave been previously disclosed by others. Similarly, the use of noiseradar for detecting the presence of an occupant within a vehicle or ofany object within a particular range of a vehicle is also not believedto have been previously disclosed by others. By setting the correlationinterval, any penetration or motion of an object within that intervalcan be positively detected. Thus, if interval is sent at 2 meters, forexample, the entire interior or nearby exterior of a vehicle can bemonitored with one simple device. If any object is moving within thevehicle, then this can readily detected. Similarly, the space beingmonitored can be limited to a portion of the interior of the vehiclesuch as the right passenger seat or the entire rear seat. In thismanner, the presence of any moving object within that space can bedetermined and thus problems such as a hiding assailant or a child oranimal left in a parked car can be addressed. A device placed in thetrunk can monitor the motion of any object that has been trapped withinthe trunk thereby eliminating that well-known problem.

The radar system to be used for the precise positioning system can alsobe used for monitoring the space around a vehicle. In this case, asimple structure involving the placement of four antennas on the vehicleroof, for example, can be used to locate and determine the velocity ofany object approaching or in the vicinity of the vehicle. Using neuralnetworks and the reflection received from the four antennas, thelocation and velocity of an object can be determined and by observingthe signature using pattern recognition techniques such as neuralnetworks the object can be identified. Each antenna would send andreceive noise radar waves from an angle of, for example, 180 degrees.One forward and one rear antenna could monitor the left side of thevehicle and one forward and one rear antenna could monitor the rightside. Similarly, the two rear antennas could monitor the rear of thevehicle and the two forward antennas could monitor the forward part ofthe vehicle. In this manner, one simple system provides rear impactanticipatory sensing, automatic cruise control, forward impactanticipatory sensing, blind spot detection, and side impact anticipatorysensing. Since the duty cycle of the precise positioning system issmall, most of the time would be available for monitoring the spacesurrounding the vehicle. Through the choice of the correlation intervaland coding scheme (CDMA, noise, etc.), the distance monitored can alsobe controlled.

In addition to the position-based code, an ID related to the type ofvehicle could also be part of the code so that an interested vehicle mayonly wish to interrogate vehicles of a certain class such as emergencyvehicles. Also having information about the vehicle type communicated tothe host vehicle can quickly give an indication of the mass of theoncoming vehicle which, for example, could aid an anticipatory sensor inprojecting the severity of an impending crash.

Although it has been generally assumed that vehicle-to-vehiclecommunication will take place through a direct link or through an ad-hocor mesh network, when Internet access becomes ubiquitous for vehicles,this communication could also take place via the Internet through aWi-Fi or Wimax or equivalent link. Additionally, the use of an ad-hoc ormesh network for vehicle-to-vehicle communication especially to sending:relative location, velocity and vehicle mass information for collisionavoidance purposes; GPS, DGPS, PPS related information for locationdetermination and error correction purposes; traffic congestion or roadcondition information; weather or weather related information; and,vehicle type information particularly for emergency vehicleidentification so that the host vehicle can take appropriate actions toallow freedom of passage for the emergency vehicle, are consideredimportant parts of the present inventions. In fact, a mesh or ad-hocnetwork can greatly improve the working of an ubiquitous WI-FI, Wimax orequivalent Internet system thereby extending the range of the wirelessInternet system.

This system also supports emergency vehicles sending warnings tovehicles that are in its path since it, and only it, will know its routefrom its present location to its destination. Such a system will permitsignificant advanced warning to vehicles on the route and also allow forthe control of traffic lights based on its planned route long before itarrives at the light. In this regard, see “Private Inventor Files PatentApplication For Telematics-Based Public and Emergency First RespondersSafety Advisory System”, ITS America News Release Feb. 13, 2004, for adiscussion of a primitive but similar system.

An alternate approach to using the code-based on location system is touse a vehicle ID system in connection with an easily accessible centraldatabase that relates the vehicle ID to its location. Then communicationcan take place via a code-based on the vehicle ID, or some equivalentmethod.

9. Infrastructure-to-Vehicle Communication

Initial maps showing roadway lane and boundary location for the CONUScan be installed within the vehicle at the time of manufacture. Thevehicle thereafter would check on a section-by-section basis whether ithad the latest update information for the particular and surroundinglocations where it is being operated. One method of verifying thisinformation would be achieved if a satellite or Internet connectionperiodically broadcasts the latest date and time or version that eachsegment had been most recently updated. This matrix would amount to asmall transmission requiring perhaps a few seconds of airtime. Anyadditional emergency information could also be broadcast in between theperiodic transmissions to cover accidents, trees falling onto roads etc.If the periodic transmission were to occur every five minutes and if themotion of a vehicle were somewhat restricted until it had received aperiodic transmission, the safety of the system can be assured. If thevehicle finds that it does not have the latest map information,vehicle-to-vehicle communication, vehicle-to-infrastructurecommunication, Internet communication (Wi-Fi, Wi-max or equivalent), orthe cell phone in the vehicle can be used to log on to the Internet, forexample, and the missing data downloaded. An alternate is for the GEOs,LEOs, or other satellites, to broadcast the map corrections directly.

When mention is made of the vehicle being operative to performcommunications functions, it is understood that the vehicle includes aprocessor, maybe in the form of a computer, which is coupled to acommunications unit including at least a receiver capable of receivingwireless or cellphone communications, and thus this communications unitis performing the communications function and the processor isperforming the processing or analytical functions.

It is also possible that the map data could be off-loaded from atransmitter on the highway itself or at a gas station, for example, asdiscussed above. In that manner, the vehicles would only obtain that mapinformation which is needed and the map information would always be upto the minute. As a minimum, temporary data communication stations canbe placed before highway sections that are undergoing construction orwhere a recent blockage has occurred, as discussed above, and where themaps have not yet been updated. Such an emergency data transfer would besignaled to all approaching vehicles to reduce speed and travel withcare. Such information could also contain maximum and minimum speedinformation which would limit the velocity of vehicles in the area.Other locations for transmitters include anywhere on a roadway on whichthe vehicles travel, any vehicle-accessible commercial or publiclocation such as malls, at the vehicle operator's home or place ofbusiness, and even on a road sign. Moreover, if information aboutweather or road conditions in vicinity of the transmitter is obtained, amaximum speed limit for roads in the vicinity of the transmitter can bedetermined by a traffic monitoring facility based on the informationabout the weather or road conditions and provided to the transmitter fortransmission to the vehicles. This speed limit would then be conveyed tosigns associated with, in or on the roads affected by the weather orroad conditions.

There is other information that would be particularly useful to avehicle operator or control system, including in particular, the weatherconditions, especially at the road surface. Such information could beobtained by road sensors and then transmitted to all vehicles in thearea by a permanently installed system as disclosed above and in U.S.Pat. No. 6,662,642. Such road sensors would preferably be embedded in oralongside the road surface to obtain data about the road surface withthe data being directed to transmitters for transmission to vehicles inrange of the transmitter and traveling or expected to travel over theroad surface in or alongside which the sensors are embedded. Thetransmission technique may be as described elsewhere herein fortransmitting information to vehicles from infrastructure-basedtransmitters.

Alternately, there have been recent studies that show that icingconditions on road surfaces, for example, can be accurately predicted bylocal meteorological stations and broadcast to vehicles in the area. Ifsuch a system is not present, then the best place to measure roadfriction is at the road surface and not on the vehicle. The vehiclerequires advance information of an icing condition in order to have timeto adjust its speed or take other evasive action. The same road-based orlocal meteorological transmitter system could be used to warn theoperators of traffic conditions, construction delays etc. and to set thelocal speed limit. In general, information provided to the transmittersfor transmission to the vehicle operators can be weather information,road surface information, traffic information, speed limit information,information about construction, information about points of interest(possibly restricted based on position of the vehicle), informationabout the presence of animals in proximity to the road, informationabout signs relating to the road, accidents, congestion, speed limits,route guidance, location-based services, emergency or other informationfrom police, fire or ambulance services, or information generated byprobe vehicles. Probe vehicles are generally those vehicles whichprecede the host vehicle in time along the same highway or in the samearea.

Once one vehicle in an area has discovered an icing condition, forexample, this information can be immediately transmitted to all equippedvehicles through the vehicle-to-vehicle communication system discussedabove. In a preferred implementation, icing and other such conditionswould be sensed and the information transmitted automatically by thevehicle without driver involvement.

In view of the various types of information that can be transmitted tothe vehicle from infrastructure-based transmitters, one embodiment ofthe invention provides for a user input device on the vehicle whichenables an occupant of the vehicle to request information to betransmitted via the transmitter. The requested information is providedto the transmitter for retransmission to the vehicle. The source ofinformation might be a website accessed by the user through thetransmitter with the requested information being provided to thetransmitter and then transmitted to the vehicle.

Another manner to provide for transmission of information to the vehicleis based on satisfaction of a condition requiring transmission ofinformation to the vehicle. A condition might be detection of aparticular weather pattern, such as snow, in which case, road icinginformation is transmitted to the vehicle whenever snow is detected.

A number of forms of infrastructure-to-vehicle communication have beendiscussed elsewhere herein. These include map and differential GPSupdating methods involving infrastructure stations which may be locatedat gas stations, for example. Also communications with precisepositioning stations for GPS independent location determination havebeen discussed. Communications via the Internet using either satelliteInternet services with electronic steerable antennas such as areavailable from KVH, Wi-Fi or Wimax which will undoubtedly becomeavailable ubiquitously throughout the CONUS, for example, as discussedbelow. All of the services that are now available on the Internet plusmay new services will thus be available to vehicle operators andpassengers. The updating of vehicle resident software will also becomeautomatic via such links. The reporting of actual (diagnostics) andforecasted (prognostics) vehicle failures, derived by a diagnosticsystem on the vehicle or a diagnostic system remote from the vehicle butwhich receives data from the vehicle and returns a diagnosticdetermination, will also able to be communicate via one of these linksto the authorities, the smart highway monitoring system, vehicle dealersand manufacturers (see U.S. Pat. No. 7,082,359). Thus, the diagnostic orprognostic determination is transmitted from the vehicle to atransmitter which in turn can direct the determination to a dealer,manufacturer, vehicle owner and/or service center.

This application along with the inventions herein provide a method ofnotifying interested parties of the failure or forecasted failure of avehicle component using a vehicle-to-infrastructure communicationsystem. Such interested parties can include, but are not limited to: avehicle manufacturer so that early failures on a new vehicle model canbe discovered so as to permit an early correction of the problem; adealer so that it can schedule fixing of the problem so as to providefor the minimum inconvenience of their customer and even, in some cases,dispatching a service vehicle to the location of the troubled vehicle;NHTSA so that they can track problems (such as for the Firestone tireproblem) before they become a national issue; the police, EMS, firedepartment and other emergency services so that they can prepare for apotential emergency etc. For example in “Release of Auto Safety Data IsDisputed”, New York Times Dec. 13, 2002 it is written “After Firestonetire failures on Ford Explorers led to a national outcry over vehiclesafety, Congress ordered a watchdog agency to create an early-warningsystem for automotive defects that could kill or injure people.” Theexistence of the system disclosed herein would provide an automaticmethod for such a watchdog group to monitor all equipped vehicles on thenation's highways. As a preliminary solution, it is certainly within thestate of the art today to require all vehicles to have an emergencylocator beacon or equivalent that is impendent of the vehicle'selectrical system and is activated on a crash, rollover or similarevent.

Although the '129 patent application primarily discusses diagnosticinformation for the purpose of reporting present or forecasted vehiclefailures, there is of course a wealth of additional data that isavailable on a vehicle related to the vehicle operation, its location,its history etc. where an interested party may desire that such data betransferred to a site remote from the vehicle. Interested parties couldinclude the authorities, parents, marketing organizations, the vehiclemanufacturer, the vehicle dealer, stores or companies that may be in thevicinity of the vehicle, etc. There can be significant privacy concernshere which have not yet been addressed. Nevertheless, with the propersafeguards the capability described herein is enabled partially by theteachings of this invention.

For critical functions where a software-induced system failure cannot betolerated, even the processing may occur on the network achieving whatpundits have been forecasting for years that “the network is thecomputer”. Vehicle operators will also have all of the functions nowprovided by specialty products such as PDAs, the Blackberry, cell phonesetc. available as part of the infrastructure-to-vehicle communicationsystems disclosed herein.

There are of course many methods of transferring data wirelessly inaddition to the CDMA system described above. Methods using ultrawideband signals were first disclosed by ATI or ITI in previous patentsand are reinforced here. Much depends of the will of the FCC as to whatmethod will eventually prevail. Ultra wideband within the frequencylimits set by the FCC is certainly a prime candidate and lends itself tothe type of CDMA system where the code is derivable from the vehicle'slocation as determined, for example, by the GPS that this is certainly apreferred method for practicing the teachings disclosed herein.

Note that different people may operate a particular vehicle and when aconnection to the Internet is achieved, the Internet may not know theidentity of the operator or passenger, for the case where the passengerwishes to operate the Internet. One solution is for the operator orpassenger to insert a smart card, plug in their PDA or cell phone orotherwise electronically identify themselves. An embodiment of theinvention is therefore possible wherein the occupant of the vehicle isfirst identified and then information is transmitted to the vehicle viathe transmitter based on the identification of the occupant. To thisend, personal data for occupants may be stored at one or more sitesaccessible via the Internet, a determination is made after the occupantis identified as to where a particular person's personal data is stored(e.g., using a table), and then the personal data is transmitted fromthe determined storage location to the vehicle via the transmitter uponidentification of the occupant.

Cellphones and similar devices can now connect to the internetwirelessly either thought the cellphone system or through the internetwhich is now becoming more and more ubiquitous. When a person is at homeor work, he or she accesses the Internet through a PC rather than acellphone. When in a vehicle, the possibility exists for a similarinternet access with a full keyboard and large monitor which in somecases can reside on windshield. This will allow a driver, when thevehicle is autonomously driven, or a passenger at any time to surf theinternet, for example, or in all other ways operate if he or she were athome or work. This process is especially enhanced if personal files areaccessible because they reside on a server or computer that can beaccessed over the internet. Even video conferencing and other suchinteractions can take place. The fact that the vehicle can become anextension of the home and office has not been appreciated in theliterature and is an outcome of the inventions discussed herein and inparticular the combination of a vehicle and a ubiquitous internet. Theubiquitous internet is being developed for use by cellphone type devicesbut it has significant and non-obvious advantages when combined with anautomobile.

Transponders are contemplated by the inventions disclosed hereinincluding SAW, RFID or other technologies, reflective or back scatteringantennas, polarization antennas, rotating antennas, corner cube ordihedral reflectors etc. that can be embedded within the roadway orplaced on objects beside the roadway, in vehicle license plates, forexample. An interrogator within the vehicle transmits power to thetransponder and receives a return signal. Alternately, as disclosedabove, the responding device can have its own source of power so thatthe vehicle-located interrogator need only receive a signal in responseto an initiated request. The source of power can be a battery,connection to an electric power source such as an AC circuit, solarcollector, or in some cases, the energy can be harvested from theenvironment where vibrations, for example, are present. The range of alicense-mounted transponder, for example, can be greatly increased ifsuch a vibration-based energy harvesting system is incorporated.

Some of the systems disclosed herein make use of an energy beam thatinterrogates a reflector or retransmitting device. Such a device can bea sign as well as any pole with a mounted reflector, for example. Insome cases, it will be possible for the infrastructure device to modifyits message so that when interrogated, it can provide information inaddition to its location. A speed limit sign, for example, can return avariable code indicating the latest speed limit that then could havebeen set remotely by some responsible authority. Alternately,construction zones frequently will permit one speed when workers areabsent and another when workers are present. The actual permitted speedcan be transmitted to the vehicle when it is interrogated or as thevehicle passes. Thus, a sign or reflector could also be an active signand this sign could be an active matrix organic display and solarcollector that does not need a connection to a power line and yetprovides both a visual message and transmits that message to the vehiclefor in-vehicle signage. Each of these systems has the advantage thatsince minimal power is required to operate the infrastructure-basedsign, it would not require connection to a power line. It would onlytransmit when asked to do so either by a transmission from the vehicleor by sensing that a vehicle is present.

A key marketing point for OnStar® is their one button system. This ideacan be generalized in that a vehicle operator can summon help orotherwise send a desired message to a remoter site by pushing a singlebutton. The message sent can just be a distress message or it canperform a particular function selected by the vehicle depending on theemergency or from a menu selected by the operator. Thus, the OnStar™ onebutton concept is retained but the message can be different fordifferent situations.

9.1 General

In order to eliminate fatalities on roads and mitigate congestion, it iscritical that vehicles communicate with each other. The type ofcommunication can take at least two forms, that which is time criticalsuch when two vehicles are about to collide and that which can have somedelay such as information that the road is icy 2 miles ahead. Timecritical communication is discussed above. This section will concentrateon the not time-critical communication which can also includeinformation from a vehicle that passed through an area an hour prior tothe subject vehicle or information derived from a server that may not benear the vehicle. Thus, this second type of communications can involvean entity that is not a vehicle such as a network server. In many cases,such a server will be required such as when a vehicle transmits apicture of an accident that needs to be interpreted before it can beadded as a temporary update to a map of the area.

Referring to FIG. 26 to explain this multi-form of communications, amethod for transmitting information to a host vehicle traveling on aroad using two different types or ways of communications in accordancewith the invention includes generating information from one or moresources thereof to be wirelessly transmitted to an information receivingsystem resident on the host vehicle during travel of the vehicle 280.The sources may be other vehicles on the road(s) on which the vehicle istraveling or about to or expected to travel, or infrastructurefacilities, e.g., stations or transmitters. Thus, the information may beabout one or more roads on which the host vehicle will travel in thefuture from other vehicles which traveled the road prior to the hostvehicle.

The information is then prioritized to distinguish between highpriority, time-critical information of immediate relevance to operationof the vehicle and low priority, non-time-critical information ofnon-immediate relevance to the operation of the host vehicle 282. Thisprioritization may be performed by the information receiving systemresident on the vehicle, e.g., based on an initial transmission fromeach source, or at a data storage facility separate and apart from thehost vehicle at which the information is being gathered. Theprioritization may be performed based on the current position of thehost vehicle, the location of the source and/or identity of the source.Some sources can always be considered high priority sources, e.g.,vehicles within a pre-determined range and in an expected path of travelof the host vehicle.

In particular when prioritization is performed by the informationreceiving system resident on the vehicle, it can be performed using themethod described above with reference to FIG. 20 to prioritize thereceived information in the form of waves or signals, i.e., filtertransmissions from transmitters. That is, any transmission from aparticular transmitter deemed to be a transmission of interest (based ondecoding of the initial part of the transmission 252 a) may beconsidered high priority information whereas any transmission from atransmitter not deemed to contain information of interest (based ondecoding of the initial part of the transmission 252 a), is consideredlow priority information.

High priority information 284, such as information from vehicles inclose proximity to the host vehicle and information potentially usefulor necessary for collision avoidance, is preferably transmitted directlyfrom the source 286. This ensures that the host vehicle will immediatelyhave information necessary for it to continue safe operation of thevehicle, e.g., by avoiding collisions with other proximate vehicles orinfrastructure.

Low priority information 288, or any other information not deemed highpriority, is gathered at the data storage facility 290 and directedtherefrom to the host vehicle using the ubiquitous network describedbelow, e.g., the Internet 292.

9.2 Ubiquitous Broadband Network

External monitoring, as discussed in U.S. patent application Ser. No.11/183,598 filed Jul. 18, 2005 and published as 20050278098, so far hasbeen concerned with a host or resident vehicle monitoring the space inits environment. Usually, there are vehicles that precede the hostvehicle and experience the same environment prior to the host vehicle.Information from such vehicles, which can be called “probe” vehicles,can be communicated to the host vehicle to aid that vehicle in its safetravel. This is the subject of communication between vehicles discussedabove. Generally, communication between vehicles is composed of thatwhich should be transmitted in the most expedient fashion to aid incollision avoidance as discussed above and that where some delay can betolerated. For the first type, a broadcast protocol, ad-hoc or meshlocal network is preferred where each vehicle transmits a message tosurrounding vehicles directly and with or without employing networkingprotocols, error correction, handshaking depending on the urgency of themessage etc. When many vehicles are trying to communicate, the hostvehicle needs to have a method for determining which vehicle to listento which can be done, for example, by a CDMA type system where the codeis a function of the transmitting vehicle's location such as its GPScoordinates. The receiving vehicle with a resident map can determine thecodes where potentially threatening vehicles are resident and listenonly to those codes, as discussed above.

For the second type of communication, the Internet or similar ubiquitoussystem is possible. Each probe vehicle would communicate information,such as the existence of a new construction zone, a patch of ice, fog orother visibility conditions, an accident or any other relevantinformation, to a central source which would monitor all suchtransmissions and issue a temporary map update to all vehicles in thevicinity over the Internet, or equivalent. If the probe vehicle cameupon an accident, then such a vehicle can also transmit one or morepictures of the accident to a central control station (which monitorsand controls the central source). A probe vehicle may be any equippedvehicle. The picture(s) could be transmitted automatically without anyaction on the part of the driver who may not even be aware that it isoccurring. The central control station could then determine the nature,seriousness, extent etc. of the accident (either with manual input orthrough software trained to perform these functions) and issue ameaningful update to a map of the area and later remove the update whenthe accident is cleared. Removal of the update can be performed manuallyor through subsequent analysis of the accident location. This willpermit timely display of the accident on a map display to equippedvehicles. Each passing vehicle, for example, could be instructed by thecentral control station to photograph and send the picture to thecentral control station so that it would know when the accident has beencleared.

This idea can be extended to cover other hazards. If some probe vehiclesare equipped with appropriate sensors such as radiation, chemical and/orbiological sensors, an early warning of a terrorist attack can betransmitted to the central control station all without any action on thepart of the vehicle operator. A probe vehicle can be any equippedvehicle. Additionally, routine probe vehicle reports can be sent overthe network. While on the subject of chemical sensors, a SAW or otherchemical sensor can be put into the heating and air-conditioning systemand monitor the presence of alcohol fumes in the car and transmit datato the authorities if a positive reading is achieved. Similarly,chemical sensors can be placed in all cargo containers, trucks and othervehicles to warn the authorities when such vehicles containingexplosives or other hazardous chemicals are present or beingtransported. Furthermore such a system can monitor and report on airpollution and carbon monoxide and other fumes inside or emanating fromany vehicle. Monitoring and tracking of trucks, cargo containers andother vehicles in general to prevent theft and/or for homeland securityapplications are greatly facilitated. Similarly, systems to warn ofhijacking or carjacking can be greatly facilitated by a ubiquitousInternet or equivalent. Stolen car tracking and recovery efforts wouldalso be facilitated as would the notification of a vehicle break-in.

In general, any information that can be sensed by a vehicle traveling ona roadway, including the maintenance state of the roadway itself, can beautomatically monitored and relevant information can be transmittedautomatically over the Internet, or equivalent, to a central controlstation, or centralized data source monitored and controlled thereby,along with appropriate pictures if available. This can include roadcondition monitoring such as for potholes etc., transmitting warnings ofslippery roads, bad whether, changed speed limits and construction zonesincluding the sending of photographs or video of any place where theroad and/or traffic appears to be improperly functioning such asresulting from an accident, impact with a deer, mudslide, rock slide,etc. Other examples include highway spills, boxes fallen from vehicles,the reporting of vehicle and other fires, the reporting of any anomalycan be done by pictures or a recorded voice. Furthermore, visibilityconditions, which can be used for setting speed limits and also forsetting the maximum speed that a vehicle is permitted to travel, can bereported if the vehicle has such measuring equipment. All such reportingexcept that requiring a voice input can be done automatically orinitiated by a vehicle occupant.

This assumes the existence of a ubiquitous Internet, or equivalent. Thisis believed to be the least expensive way of providing such a capabilityto the approximately 4 million miles of roads in the continental US.Proposals are now being considered to put transceivers every 100 metersalong the major highways in the US at an installation cost of billionsof dollars. Such transceivers would only cover the major highways eventhough the majority of fatal accidents occur on other roadways. Themaintenance cost of such a system would also be prohibitive and itsreliability questionable. For far less money, the continental US can becovered with IEEE 802.11-based systems such as Wimax or equivalent. Suchtransceivers can each cover up to a radius of 30-50 miles thus requiringonly approximately 500 to 1000 such stations to cover the entirecontinental US. More units would be required in densely populated areas.The cost of such units can be as low as a few thousand dollars each buteven if they cost a million dollars each, it would be a small costcompared with the alternative roadside transceivers.

Initially, it is contemplated that some areas of the country will nothave such 802.11 or equivalent stations. For those areas, map updatesand all other information described herein and especially in thissection can be transmitted by a variety of methods including a stationon satellite radio or some other satellite transmitting system, throughthe cell phone network or any other existing or special communicationsystem including normal radio and TV stations. If the selected systemdoes not support two way communications, then the messages created bythe probe vehicle can be stored and transmitted when access to theInternet is available. A probe vehicle can be a specially equippedvehicle or all or any vehicles with the appropriate equipment.

Eventually, all cars will be connected with a combination of a broadcastand/or local network (e.g. mesh or ad-hoc) system for collisionavoidance and ubiquitous Internet connections for map-based road hazardsthat are discovered by the vehicle. As a vehicle travels down a road anddiscovers an accident for example, a photograph of that accident will bestored and uploaded to the Internet for interpretation by a humanoperator who will then download a message based on the map location ofthe accident to warn other vehicles that are in the vicinity until theaccident is cleared up which can be determined by another probe vehicle.

When all cars have the system, there will be much less need forsurround-vehicle-monitoring except for searching for bicycles,motorcycles, pedestrians, animals, land slides, rocks, fallen trees,debris etc. All other vehicles will be properly equipped and the RtZF®can be on special lanes that permit autonomous vehicles or at leastproperly equipped vehicles.

There should not be any obstacles on the highway and when one isdiscovered, it should be photographed and uploaded to the centralstation via the Internet for proper handling in terms of warnings andremoval of the hazard. Until the time comes when this network iseverywhere, alternate systems can partially fill in the gaps such as XMradio and other satellite-based systems. This could be used only fordownloading map changes. For uploading information, the vehicles wouldwait, maintaining data to be sent to a database until they have a directInternet connection.

To achieve ubiquitous Internet coverage, IEEE 802.11 or Wi-Fi stations(or WiMAX or WiMobile or equivalent) would be placed around the nation.If, for example, each station (also referred to as transmitters herein)had a radial range of 30-50 miles or more than approximately 500 to 1000such stations could be strategically placed to provide nationwidecoverage. It is anticipated that the range of such stations will besubstantially increased but that the number of required stations willalso increase as usage of the ubiquitous Internet, or equivalent,network also increases. In that case, private industry can be earningrevenues through non-safety use access charges. An estimate of the costof a typical station is between $10,000 and $100,000 most of which wouldbe for the land and installation. The total cost thus would be around amaximum of $100 million which is a small fraction of the multi-billiondollar estimate by the Federal Highway Department to implement theirproposed DSCR system with transceivers every 100 meters along theFederal Highway System, a system that would leave most of the nationunprotected and in general be of marginal value. There are many towersin place now for use by radio and TV stations and cellular telephones.It is expected that such towers can also be used for this ubiquitousnetwork thus reducing the installation costs. In fact, the cellphonecompanies are likely to be the main providers of the ubiquitousinternet.

Such a proposed system could also broadcast a timing signal, which couldbe a repeat of a satellite timing signal or one derived from several GPSsatellites, as well as the differential corrections to supportDifferential GPS (DGPS). A vehicle equipped with a processor capable ofposition determination would thus receive such signals form thestations, e.g., DGPS correction updates, and together with GPSinformation received from satellites, determine its position. It couldeven broadcast a GPS-type signal and thus eliminate dependence of theRtZF® system on GPS. This might require an atomic clock which could betoo expensive for this system. However, the timing can come from thecorrected GPS signals received at the station. In other words, anyonemight be able to obtain centimeter level position accuracy without GPS.This concept may require a mapping of multipath delays in some urbanareas.

Such a ubiquitous Internet system could also provide continuous trafficmonitoring and updates, route guidance supporting information as well asweather information, automatic collision notification, diagnostic andprognostic telematics communications to the manufacturer, dealer orrepair facility etc., and in fact, all telematics transmissions would beeasily achieved with such an Internet system. Biometrics informationtransfer is facilitated when such sensors are on the vehicle. This canbe used for access to secure locations and to verify the identity of avehicle operator. The general sending of alarms and warnings to and fromthe vehicle for any reason including amber alert messages is alsogreatly facilitated.

Looking further, ubiquitous Internet could eliminate all communicationsystems that are currently used in the US including radio, TV, Cellularphones, XM radio and all satellite communications that originate and endup in the continental US, telephone, OnStar® and all telematics, DSRC.Everyone could have one phone number and one phone that would workeverywhere. Thus it could lead to the elimination of cellular phones asthey are known today, the elimination of the wired telephone system, oftelevision and radio stations, of cable television and Internetservices, and maybe the elimination of all earth to satellite-to-Earthcommunications.

Other applications include remote sensing applications for home and boatsecurity and homeland security applications, for example. Any point onthe continental US would be able to communicate with the Internet. Ifthis communication happens only occasionally, then the power can beminimal and can be boosted by some form of energy harvesting and thussuch a sensor could operate from years to infinity on rechargeablebatteries without a power connection. For example, all monitoring andtracking operations that require satellite communication such asdisclosed in U.S. patent application Ser. No. 10/940,881 and publishedas 20050046584 could be handled without satellite communication for thecontinental United States.

A significant use for such a ubiquitous network is to permit rapid andfrequent upgrades to the vehicle resident map. This is particularlyimportant for The Road to Zero Fatalities®-based systems (RtZF®). Mapupgrades can include the existence of an accident, ice, poor visibility,new temporary speed limit, traffic congestion, construction, mud slide,and countless other situations that can affect the smooth passage of avehicle on a roadway. These map upgrades can be temporary or permanent.Also for RtZF® and other such systems relying on DGPS for their locationinformation, the DGPS corrections can be frequently transmitted from acentral station using the ubiquitous network. Similarly, should anyvehicle discover that this information is faulty, or that the map isfaulty for that matter, an immediate message can be sent to theappropriate central station for action to correct the error.

An entire series of telematics services can also make use of aubiquitous network including all of the features currently using theOnStar® system. These would include concierge service, route guidance,remote door unlock, automatic crash notification, stolen vehicletracking, and other location-based services. Other location-basedservices include the location of nearest facilities such as hospitals,police stations, restaurants, gas stations, vehicle dealers, service andrepair facilities, the location of the nearest police officer or patrolcar, the location of the nearest parking facility that has a parkingspace available and the location of a parking space once the driver isin the facility. The notification of a towing service, such as AAA, whenthat service is required can be enabled. Such information can betransmitted via the infrastructure-based transmitters.

Additional services that could be enabled by the ubiquitous networkinclude automatic engine starting to pre-warm or pre-cool a vehicle,e-mail, voicemail, television, radio, movie and music downloads,synchronizing of the vehicle computer with a home or office orhotel/motel in room computer, text messages between vehicles or otherlocations for display and/or audio transmission, emergency in-vehiclesignage including a terrorist attack, tornado, cyclone, hurricane,tsunami, or similar warnings, security gate and/or door opening orunlocking, automatic entrance to secured areas where both vehicle andbiometric identification is required, rapid passage through borders byauthorized personnel, garage door opening, turning on/off of houseinside lights or outside (walk, driveway, house, etc.) lights, theability to transmit vocal messages into a vehicle such as from a policeofficer or other authority figure, speed control and vehicle disablingby authorities which among other things would prevent high-speed chasesas the police will have the ability to limit the speed of a vehicle orshut it down.

Other enabled services include transmission of in-car picturesespecially after an accident or when the police want to know who wasdriving, signaling of an emergency situation such that the vehicle isgiven emergency vehicle priority such as one when a woman is in laborand might deliver or a person is suffering a heart attack,simultaneously the nearest hospital can be notified to expect theemergency. Additional services include control of traffic lights and anindication of the status of the traffic light, and the same for railroadcrossings and the prevention of vehicles running stoplights or stopsigns.

Additional enablements include emergency vehicle alert to cause peopleto move to the right or otherwise out of the path, automatic tolling andvariable tolling, vocal communication including voice over IP calls,transmission of driver health status information (heartbeat, bloodpressure, etc.), use of voice recognition or voice print foridentification, transmission of various vehicle information includingthe vehicle identification number and transmission of the location ofthe vehicle to businesses and friends when authorized permitting parentsto know where their children are or the authorities to know whereparolees are.

Tourists can find this service particularly useful when they need onlypoint a ranging laser at a point of interest and the GPS coordinates canthen be passed to the appropriate service that can provide informationabout the point of interest. This can also be useful for professionalsallowing them to instantly download building plans, utilities locations,sewers, etc. Additionally, any information that is available on networkresident maps that is not available in the vehicle resident map can betransferred to the vehicle for informational purposes or for display orany other purpose. A key usage will be for updates to the vehicle'sdigital maps and perhaps the map software. Similarly, any vehicleresident software updates can take place seamlessly. Finally, if theauthorized vehicle operator has in his or her possession a properlyenabled cell phone or PDA or other such device, many of the featureslisted above become available to the user. The device can have propersecurity safeguards such as a biometric ID feature to preventunauthorized use. One function would be for the user to find where he orshe parked the car.

There are many innovative business opportunities that are also enabledand a few will now be discussed. A key opportunity which can enable thecreation of the ubiquitous network would be a charging system wherebythe users of the network can be charged a nominal fee based on bytestransferred, for example, to pay for the installation and maintenance ofthe equipment. Thus a business model exists where one or more companiesagree to install a nationwide ubiquitous Internet service in exchangefor such fees. This could be done piecemeal but after a while peoplewill gravitate to the new, almost free, service and usage will explode.The network can of course be used to pay for tolls, fast food andcountless other services including gasoline. Most such facilitiesalready have an internet connection. An unlimited number or other useswill become obvious in light of the above disclosure. For example, auser can be notified by a bank or other bill paying service to obtainauthorization to pay a particular bill. There will be a host ofadditional opportunities to land-based fixed or non-vehicle-basedInternet users that are enabled by the ubiquitous network andadditionally by the connection of vehicles to that network.

Many of the above services are now being enabled over other telematicsnetworks and many more of these services can now be implemented usingthose networks until the ubiquitous network is fully implemented. Thus,implementation of these as yet unimplemented services using other thanthe ubiquitous network is contemplated herein.

Others of course have been talking about large hot spots but other thanvague statements that the Internet should be everywhere, no one hasprovided a plan, or even a need, that would place Internet availabilityon all roads in the continental United States (see, e.g., H. Green “Nowires, No rules” Business Week online Apr. 26, 2004). What can drivethis ubiquitous concept is the safety aspect of automobiles as opposedto the commercial aspects of movie downloads etc. For commercialsuccess, the network need not be available on every back road where asit would be required for safety purposes.

As a vehicle travels, it will pass through different cells in theubiquitous network and control will have to pass from one cell toanother. Fortunately, this is a similar problem that has been solved forcell phones and thus should not be a problem for the network.Additionally, it has already been solved by at least one group asreported in an article in Science Daily Apr. 20, 2004 “Faster HandoffBetween Wi-Fi Networks Promises Near-Seamless 802.11 Roaming”.

9.3 Electronic Local and Emergency Communication from Infrastructure

There are many instances where it can be desirable for the localinfrastructure to communicate with vehicles in the vicinity. In onecase, it might be desirable for a local stop light to determine fromsuch communication that there are some vehicles approaching anintersection from the North but none from the East or West. In such asituation, the stoplight can become or remain green for the North-Southtraffic making it unnecessary for such traffic to stop (see, e.g., P.Ball “Beating the Lights”, Nature News, Apr. 12, 2003 where majorityrule can control stop lights).

In another situation, a temporary road sign can send an electronicmessage to vehicles approaching a construction zone to slow down and beprepared to stop. Back to the stoplight, in an Associated Press article“Cameras catch thousands going through red lights”, Jul. 22, 2005, it isreported that in two towns in Maine, “Cameras recorded nearly 5,000motorists running red lights at five intersections in Auburn andLewiston in a test program on whether cameras are an effective way tocurb traffic violations”. A communication system from the stoplight tothe vehicles can warn the driver if he or she is going too fast and evencause the vehicle to slow and even stop if the warning is ignored. Infact, the stoplight-to-vehicle communication system can even inform thedriver as to how much time remains before the light is going to change.

In still another situation, reflectors along the highway or even onother vehicles can be designed to transmit some minimal informationthrough the pattern of light that is reflected.

9.4 Precise Positioning without GPS

Use of MIR or the reflection from fiduciary points along the roadwayproviding such objects are on the vehicle resident maps is disclosed inthe above-referenced patents to ITI and herein. An interesting variationof this concept can be accomplished using some of the ideas disclosed inFullerton et al. (U.S. Pat. No. 6,774,846). For this implementation, oneapproach is to have each vehicle transmit a coded signal either usingthe methods of the '846 patent or a CDMA or other approach that would beconsistent with the vehicle-to-vehicle communication approach describedabove. The vehicle would transmit such a signal which would then causethe infrastructure-resident station to synchronize its clock with thereceived train of pulses, or other coded signal, and return it to thesending vehicle. That vehicle would then determine the time delaybetween its repeating sent code and the received code to determine thedistance to the infrastructure-resident station. If three such stationsrespond, then the vehicle can determine its exact location to centimeteraccuracy. If two respond and the vehicle has the exact location of thetwo stations on its map, then through multiple transmissions, thevehicle can also determine its exact location.

This system can also be used to determine the relative location of twovehicles. Furthermore, if one vehicle has recently had its positionupdated by such a method, it can determine the GPS corrections andtransmit them to vehicles in the vicinity as discussed elsewhere herein.This also solves the atomic clock problem that was apparent in theLemelson '500 patent discussed above. By this method, absolute time isnot required. Thus, by using this method, the Lemelson pseudolitesbecome feasible.

9.5 DGPS Corrections from Infrastructure

Discussed above are many methods of obtaining the DGPS corrections froman infrastructure-resident station. These corrections can be passed fromvehicle to vehicle or from a local station to one or more vehiclesproviding a local area differential GPS system alone with thepossibility of kinematic GPS. Alternately, when such a localdifferential station is not available, a wide area differential GPS setof corrections can be obtained from the ubiquitous network. Suchcorrections can be obtained from looking at the corrections at severalstations around the continental United States and creating a map of theatmospheric diffraction caused delays for the entire country. Local areaDGPS provides the possibility for accuracies of approximately 2 cm (1sigma) or less while wide area DGPS is closer to 10 cm.

9.6 Route Guidance

The determination of a route that a vehicle should take to go from itspresent location to its destination can be accomplished using avehicle-resident system. A central server can be used to derive the GPScoordinates of the destination if it is not known based on its address,phone number or other identifying information. Once the route has beenselected, the network can be checked to see if there is any congestion,tie-ups or other problems along the route and if so, then the driver canbe asked as to whether the system should choose an alternate route andthe process repeated.

9.7 Display of Pictures

Many times a picture can replace countless words in describing to adriver the destination. Also, pictures can be valuable if the vehicledriver is a tourist and would like to know about points of interest thathe or she is passing. Additionally, a picture can be of value forassessing the seriousness of congestion ahead or any other anomaly thatmight cause the driver to wish to take another route. Such pictures cancome from traffic helicopters or other cameras that have a view of theroad, satellites or Google Earth or equivalent. These pictures can bedisplayed on any convenient display including a head-up display and ifthe vehicle has an occupant position sensor, so that the position of theeyes of the occupant can be found, then the picture can be displayed onthe windshield at the proper location in the driver's field of view.

9.8 In-Vehicle Signage

As discussed above, the ability to send text messages to and from avehicle can be important in making the driver's time more efficient.This is particularly useful for truck drivers, salesmen and others thatspend a great deal of time on the road as part of their business. Suchmessages can inform the driver of a canceled or changed meeting, keynews events that can affect the driver etc. Such text messages are lessdistracting than phone calls since the messages can be transmittedanytime and read when convenient. They can also be used to sendemergency messages to all vehicles in the area telling them that theroad ahead has turned icy, for example.

A key use for in vehicle signage is to allow the driver to see a signthat he or she may have missed due to a blocking truck, fog or for anyother reason. At will, the driver can scroll forward or backward to readsigns that are upcoming or that he or she has passed. Signs can also betranslated into any language where that might be desirable for travelersin countries where their language skills are poor.

9.9 Network is the Computer

One serious problem with vehicles is that they last a long time,typically 10 or more years before they are retired form use. Computerhardware and software, on the other hand, is continuously changing andthis rate of change in thought to be exponential. A vehicle that is 10years old certainly will not have hardware that is capable of processingrecently developed programs. One solution is to adopt the CiscoCorporation approach that “the network is the computer”. Although thisconcept is slow to be adopted by businesses and individual computerusers, it does make sense for automobiles and other vehicles providingthe network is ubiquitous and reliable. This then is another argumentfor the ubiquitous broadband network discussed above. Thus, any andevery vehicle would have the equivalent of the latest hardware andsoftware for the payment of a subscription, for example. This wouldprovide recurring revenues for businesses that created and maintainedsuch hardware and software. The pull factor that would encourage peopleto subscribe to the service would be that they would be permitted totravel on safe high speed lanes. Cars that failed to maintain theirsubscriptions would be forced to use either vehicle resident or earlyversions of the software and hardware and would not be permitted totravel on safe, high speed roads.

9.10 Summary

To summarize the foregoing description of a new method for transmittinginformation to a host vehicle traveling on a road. FIG. 27 shows aschematic of the flow of data. Information to be wirelessly transmitted,preferably via a ubiquitous network, to an information receiving systemresident on the “host” vehicle 294 during travel of the vehicle 294 isgenerated by one or more information sources which include “probe”vehicles 294, traffic cameras 296 and road sensors 298. The probevehicles 294 provide information about one or more roads on which thehost vehicle will travel or is expected to travel at some time in thefuture, the difference being if the road the vehicle expects to travelon is congested, the driver of the host vehicle can take an alternativeroute. Other sources of information include data channels with weatherinformation, i.e., meteorological reports, and traffic information suchas that provided by highway, bridge and tunnel operators andmunicipalities. It is important to note that the host vehicle can alsobe a probe vehicle, in that information it obtains can be used fortransmission to vehicles behind it on the same path, and that a probevehicle can be a host vehicle in that information it receives wasobtained by vehicle in front of it on the same path. As such, FIG. 27shows element 294 designated as vehicles.

This information is sent from the various sources, preferably over aubiquitous network, and is gathered in a central data storage,monitoring and/or processing facility 300, e.g., a network server ormainframe computer, which may entail directing the information sourcesto respond to inquiries for information from the data facility orprogramming the information sources to automatically provide theinformation at set times. The probe vehicles 294 can also continuallyprovide information limited only by the components of the transmissionunit thereon. The data facility 300 can also be programmed toautomatically access data channels on a regular basis to obtain currentinformation about roads and weather. Although the data facility 300gathers a large amount of information, not all of the information willbe directed to the vehicle 294, i.e., only potential relevantinformation will be considered for each vehicle 294 in communicationwith the data facility 300. Thus, different subsets of the totalavailable information will be generated for each host vehicle 294.

The data facility 300 includes software and hardware components whichenables it to prioritize the information to distinguish between highpriority, time-critical information of immediate relevance to operationof the host vehicle 294 and low priority, non-time-critical informationof non-immediate relevance to the operation of the host vehicle 294. Itcan thus be programmed to control and communicate with the informationreceiving system to cause it to receive and process high priorityinformation before low priority information, the transmission of both ofwhich are directed by the data facility 300. Prioritization can beestablished based on the current position of the host vehicle 294.

Data facility 300 can be programmed to maintain a map of roads residentin host vehicles by transmitting map updates necessary for the maps tobe current, the map updates being generated based on the gatheredinformation. If a temporary map update is created based on a change inthe operability or functionality of a road, e.g., based on a trafficaccident, the data facility 300 is programmed to continuously monitorthe change to determine when the use of the road reverts to a statepreceding the change. When this happens, notification of this reversionis transmitted to the host vehicle, e.g., via another map update.

Data facility 300 communicates with traffic control devices 302 via theubiquitous network of transceivers. It can thus analyze vehiculartraffic and control the traffic control devices based on the vehiculartraffic, e.g., regulate the pattern of green lights to optimize traffic,eliminate traffic jams and expedite emergency response vehicles.

Data facility 300 also communicates with an emergency response facility304 to direct aid to a host vehicle when necessary or to the site of anaccident as determined by the information gathered from the sourcesthereof.

Data facility 300 also communications with Internet content providers306 to allow the occupants of host vehicles to request Internet contentover the ubiquitous network.

It should be understood that the transmission of information betweenvehicles is one exemplifying use of the invention which also encompassesgenerating information from other types of mobile units, transmittingthe information to a common monitoring station, generating at themonitoring station an update for, e.g., a map, based on the transmittedinformation, and then transmitting the update to each of the mobileunits.

10. The RtZF® System

10.1 Technical Issues

From the above discussion, two conclusions should be evident. There aresignificant advantages in accurately knowing where the vehicle, theroadway and other vehicles are and that possession of this informationis the key to reducing fatalities to zero. Second, there are manytechnologies that are already in existence that can provide thisinformation to each vehicle. Once there is a clear recognized directionthat this is the solution then many new technologies will emerge. Thereis nothing inherently expensive about these technologies and once theproduct life cycle is underway, the added cost to vehicle purchaserswill be minimal. Roadway infrastructure costs will be minimal and systemmaintenance costs almost non-existent.

Most importantly, the system has the capability of reducing fatalitiesto zero!

The accuracy of DGPS has been demonstrated numerous times in smallcontrolled experiments, most recently by the University of Minnesota andSRI.

The second technical problem is the integrity of the signals beingreceived and the major cause of the lack of integrity is the multi-patheffect. Considerable research has gone into solving the multi-patheffect and Trimble, for example, claims that this problem is no longeran issue.

The third area is availability of GPS and DGPS signals to the vehicle asit is driving down the road. The system is designed to toleratetemporary losses of signal, up to a few minutes. That is a primefunction of the inertial navigation system (INS or IMU). Prolongedabsence of the GPS signal will significantly degrade system performance.There are two primary causes of lack of availability, namely, temporarycauses and permanent causes. Temporary causes result from a car drivingbetween two trucks for an extended period of time, blocking the GPSsignals. The eventual solution to this problem is to change the laws toprevent trucks from traveling on both sides of an automobile. If thisremains a problem, a warning will be provided to the driver that he/sheis losing system integrity and therefore he/she should speed up or slowdown to regain a satellite view. This could also be done automatically.Additionally, the vehicle can obtain its location information throughvehicle-to-vehicle communication plus a ranging system so that if thevehicle learns the exact location of the adjacent vehicle and itsrelative location, then it can determine its absolute location. If theprecise positioning system is able to interrogate the environment, thenthe problem is also solved via the PPS system.

Permanent blockage of the GPS signals, as can come from operating thevehicle in a tunnel or a downtown area of a large city, can be correctedthrough the use of pseudolites or other guidance systems such as theSnapTrack system or the PPS described here. This is not a seriousproblem since very few cars run off the road in a tunnel or in downtownareas. Eventually, it is expected that the PPS will become ubiquitousthereby rendering GPS as the backup system. Additional methods forlocation determination to aid in reacquiring the satellite lock includevarious methods based on cell phones and other satellite systems such asthe Skybitz system that can locate a device with minimal information.

The final technical impediment is the operation of the diagnostic systemthat verifies that the system is operating properly. This requires anextensive failure mode and effect analysis and the design of adiagnostic system that answers all of the concerns raised by the FMEA.

10.2 Cost Issues

The primary cost impediment is the cost of the DGPS hardware. A singlebase station and roving receiver that will give an accuracy of about 2centimeters (16) currently costs about $25,000. This is a temporarysituation brought about by low sales volume. Since there is nothingexotic in the receiving unit, the cost can be expected to follow typicalautomotive electronic life-cycle costs and therefore the projected highvolume production cost of the electronics for the DGPS receivers isbelow $100 per vehicle. In the initial implementation of the system, anOmniSTAR® DGPS system will be used providing an accuracy of about 6 cm.The U.S. national DGPS system is now coming on line and thus the cost ofthe DGPS corrections will soon approach zero.

A similar argument can be made for the inertial navigation system.Considerable research and development effort is ongoing to reduce thesize, complexity and cost of these systems. Three technologies are vyingfor this rapidly growing market: laser gyroscopes, fiber-optic lasers,and MEMS systems. The cost of these units today range from a few hundredto ten thousand dollars each, however, once again this is due to thevery small quantity being sold. Substantial improvements are being madein the accuracies of the MEMS systems and it now appears that such asystem will be accurate enough for RtZF® purposes. The cost of thesesystems in high-volume production is expected to be on the order of tendollars each. This includes at least a yaw rate sensor with threeaccelerometers and probably three angular rate sensors. The accuracy ofthese units is currently approximately 0.003 degrees per second. This isa random error which can be corrected somewhat by the use of multiplevibrating elements. A new laser gyroscope has recently been announced byIntellisense Corporation which should provide a dramatic cost reductionand accuracy improvement.

One of the problems keeping the costs high is the need in the case ofMEMS sensors to go through an extensive calibration process where theeffects of all influences such as temperature, pressure, vibration, andage is determined and a constitute equation is derived for each device.A key factor in the system of the inventions here is that this extensivecalibration process is eliminated and the error corrections for the IMUare determined after it is mounted on the vehicle through the use of aKalman filter, or equivalent, coupled with input from the GPS and DGPSsystem and the precise positioning system. Other available sensors arealso used depending on the system. These include a device for measuringthe downward direction of the earth's magnetic field, a flux gagecompass, a magnetic compass, a gravity sensor, the vehicle speedometerand odometer, the ABS sensors including wheel speed sensors, andwhatever additional appropriate sensors that are available. Over time,the system can learn of the properties of each component that makes upthe IMU and derive the constituent equation for that component which,although will have little effect on the instantaneous accuracy of thecomponent, it will affect the long term accuracy and speed up thecalculations.

Eventually, when most vehicles on the road have the RtZF® system,communication between the vehicles can be used to substantially improvethe location accuracy of each vehicle as described above.

The cost of mapping the CONUS is largely an unknown at this time.OmniSTAR® has stated that they will map any area with sufficient detailat a cost of $300 per mile. They have also indicated the cost will dropsubstantially as the number of miles to be mapped increases. Thismapping by OmniStar would be done by helicopter using cameras and theirlaser ranging system. Another method is to outfit a ground vehicle withequipment that will determine the location of the lane and shoulderboundaries of road and other information. Such a system has been usedfor mapping a Swedish highway. One estimate is that the mapping of aroad will be reduced to approximately $50 per mile for major highwaysand rural roads and a somewhat higher number for urban areas. The goalis to map the country to an accuracy of about 2 to 10 centimeters (1σ).

Related to the costs of mapping is the cost of converting the raw dataacquired either by helicopter or by ground vehicle into a usable mapdatabase. The cost for manually performing this vectorization processhas been estimated at $100 per mile by OmniSTAR®. This process can besubstantially simplified through the use of raster-to-vector conversionsoftware. Such software is currently being used for converting handdrawings into CAD systems, for example. The Intergraph Corp. provideshardware and software for simplifying this task. It is thereforeexpected that the cost for vectorization of the map data will followproportionately a similar path to the cost of acquiring the data and mayeventually reach $10 to $20 per mile for the rural mapping and $25 to a$50 per mile for urban areas. Considering that there are approximatelyfour million miles of roads in the CONUS, and assuming we can achieve anaverage of $150 for acquiring the data and converting the data to a GISdatabase can be achieved, the total cost for mapping all of the roads inU.S. will amount to $600 million. This cost would obviously be spreadover a number of years and thus the cost per year is manageable andsmall in comparison to the $215 billion lost every year due to death,injury and lost time from traffic congestion.

Another cost factor is the lack of DGPS base stations. The initialanalysis indicated that this would be a serious problem as using thelatest RTK DGPS technology requires a base station every 30 miles. Uponfurther research, however, it has been determined that the OmniSTAR®company has now deployed a nationwide WADGPS system with 6 cm accuracy.The initial goal of the RtZF® system was to achieve 2 cm accuracy forboth mapping and vehicle location. The 2 cm accuracy can be obtained inthe map database since temporary differential base stations will beinstalled for the mapping purposes. By relaxing the 2 cm requirement to6 cm or even 10 cm, the need for base stations every 30 miles disappearsand the cost of adding a substantial number of base stations is nolonger a factor.

The next impediment is the lack of a system for determining when changesare planned for the mapped roads. This will require communication withall highway and road maintenance organizations in the mapped area. Amanagement system to address this issue will evolve with systemdeployment and is not considered to be a significant impediment.

A similar impediment to the widespread implementation of this RtZF®system is the lack of a communication system for supplying map changesto the equipped vehicles. This is now being solved through theimplementation of a ubiquitous internet system such as WiMAX.

10.3 Educational Issues

A serious impediment to the implementation of this system that isrelated to the general lack of familiarity with the system, is thebelief that significant fatalities and injuries on U.S. highways are afact of life. This argument is presented in many forms such as “theperfect is the enemy of the good”. This leads to the conclusion that anysystem that portends to reduce injury should be implemented rather thantaking the viewpoint that driving an automobile is a process and as suchit can be designed to achieve perfection. As soon as it is admitted thatperfection cannot be achieved, then any fatality gets immediatelyassociated with this fact. This of course was the prevailing view amongall manufacturing executives until the zero defects paradigm shift tookplace. The goal of the “Zero Fatalities”™ program is not going to beachieved in a short period of time. Nevertheless, to plan anything shortof zero fatalities is to admit defeat and to thereby allow technologiesto enter the market that are inconsistent with a zero fatalities goal.

10.4 Potential Benefits When the System is Deployed.

10.4.1 Assumptions for the Application Benefits Analysis

-   -   The high volume incremental cost to an automobile will be $200.    -   The cost of DGPS correction signals will be a onetime charge of        $50 per vehicle.    -   The benefits to the vehicle owner from up-to-date maps and to        the purveyors of services located on these maps. will cover the        cost of updating the maps as the roads change.    -   The cost of mapping substantially all roads in the CONUS will be        $600 million.    -   The effects of phasing in the system will be ignored.    -   There are 15 million vehicles sold in the U.S. each year.    -   Of the 40,000 plus people killed on the roadways, at least 10%        are due to road departure, yellow line infraction, stop sign        infraction, excessive speed and other causes which will be        eliminated by the Phase Zero deployment.    -   $165 billion are lost each year due to highway accidents.    -   The cost savings due to secondary benefits will be ignored.

10.4.2 Analysis Methods Described.

The analysis method will be quite simple. Assume that 10% of thevehicles on the road will be equipped with RtZF® systems in the firstyear and that this will increase by 10 percent each year. Ten percent or4000 lives will be saved and a comparable percentage of injuries. Thus,in the first year, one percent of $165 billion dollars will be saved or$1.65 billion. In the second year, this saving will be $3.3 billion andthe third year $4.95 billion. The first-year cost of implementation ofthe system will be $600 million for mapping and $3.75 billion forinstallation onto vehicles. The first year cost therefore will be $4.35billion and the cost for the second and continuing years will be $3.75billion. Thus, by the third year, the benefits exceed the costs and bythe 10th year, the benefits will reach $16.5 billion compared with costsof $3.75 billion, yielding a benefits to cost ratio of more than 4.

Before the fifth year of deployment, it is expected that other parts ofthe RtZF® system will begin to be deployed and that the benefitstherefore are substantially understated. It is also believed that the$250 price for the Phase Zero system on a long-term basis is high and itis expected that the price to drop substantially. No attempt has beenmade to estimate the value of the time saved in congestion or efficientoperation of the highway system. Estimates that have been presented byothers indicate that as much as a two to three times improvement intraffic through flow is possible. Thus, a substantial portion of the $50billion per year lost in congestion delays will also be saved when thefull RtZF® system is implemented.

It is also believed that the percentage reduction of fatalities andinjuries has been substantially understated. For the first time, therewill be some control over the drunk or otherwise incapacitated driver.If the excessive speed feature is implemented, then gradually the costof enforcing the nation's speed limits will begin to be substantiallyreduced. Since it is expected that large trucks will be among firstvehicles to be totally covered with the system, perhaps on a retrofitbasis, it is expected that the benefits to commercial vehicle owners andoperators will be substantial. The retrofit market may rapidly developand the assumptions of vehicles with deployed systems may be low. Noneof these effects have been taken into account in the above analysis.

The automated highway systems resulting from RtZF® implementation areexpected to double or even triple in effective capacity by increasingspeeds and shortening distances between vehicles. Thus, the effect onhighway construction cost could be significant.

10.5 Initial System Deployment

The initial implementation of the RtZF® system would include thefollowing services:

-   -   1. A warning is issued to the driver when the driver is about to        depart from the road.    -   2. A warning is issued to the driver when the driver is about to        cross a yellow line or other lane boundary.    -   3. A warning is provided to the driver when the driver is        exceeding a safe speed limit for the road geometry.    -   4. A warning is provided to the driver when the driver is about        to go through a stop sign without stopping.    -   5. A warning is provided to the driver when the driver is about        to run the risk of a rollover.    -   6. A warning will be issued prior to a rear end impact by the        equipped vehicle.    -   7. In-vehicle signage will be provided for highway signs        (perhaps with a multiple language option).    -   8. A recording will be logged whenever a warning is issued.

10.6 Other Uses

The RtZF® system can replace vehicle crash and rollover sensors forairbag deployment and other sensors now on or being considered forautomobile vehicles including pitch, roll and yaw sensors. Thisinformation is available from the IMU and is far more accurate thanthese other sensors. It can also be found by using carrier phase GPS byadding more antennas to the vehicle. Additionally, once the system is inplace for land vehicles, there will be many other applications such assurveying, vehicle tracking and aircraft landing which will benefit fromthe technology and infrastructure improvements. The automobile safetyissue and ITS will result in the implementation of a national systemwhich provides any user with low cost equipment the ability to knowprecisely where he is within centimeters on the face of the earth. Manyother applications will undoubtedly follow.

10.7 Road Departure

FIG. 4 is a logic diagram of the system 50 in accordance with theinvention showing the combination 40 of the GPS and DGPS processingsystems 42 and an inertial reference unit (IRU) or inertial navigationsystem (INS) or Inertial Measurement Unit (IMU) 44. The GPS systemincludes a unit for processing the received information from thesatellites 2 of the GPS satellite system, the information from thesatellites 30 of the DGPS system and data from the inertial referenceunit 44. The inertial reference unit 44 contains accelerometers andlaser or MEMS gyroscopes, e.g., three accelerometers and threegyroscopes. Also, the IMU 44 may be a MEMS-packaged IMU integrated withthe GPS and DGPS processing systems 42 which serve as a correction unit.

The system shown in FIG. 4 is a minimal RtZF® system that can be used toprevent road departure, lane crossing and intersection accidents, whichtogether account for more than about 50% of the fatal accidents in theU.S.

Map database 48 works in conjunction with a navigation system 46 toprovide a warning to the driver when he or she is about to run off theroad, cross a center (yellow) line, run a stop sign, or run a redstoplight. The map database 48 contains a map of the roadway to anaccuracy of 2 cm (1σ), i.e., data on the edges of the lanes of theroadway and the edges of the roadway, and the location of all stop signsand stoplights and other traffic control devices such as other types ofroad signs. Another sensor, not shown, provides input to the vehicleindicating that an approaching stoplight is red, yellow or green.Navigation system 46 is coupled to the GPS and DGPS processing system42. For this simple system, the driver is warned if any of the aboveevents is detected by a driver warning system 45 coupled to thenavigation system 46. The driver warning system 45 can be an alarm,light, buzzer or other audible noise, or, preferably, a simulated rumblestrip for yellow line and “running off of road” situations and acombined light and alarm for the stop sign and stoplight infractions.

One implementation of the system 50 is as a system for determiningaccurate position of an object, whether a vehicle or another object theposition of which is desired, such as a cell phone or emergency locatordevice. This positioning system would therefore include a GPSpositioning system arranged to communicate with one or more satellites 2to obtain GPS signals therefrom, and which may be incorporated into theGPS and DGPS processing system 42 in the integral, combined unit 40. Acorrection unit may also be included in the unit 40, e.g., in the GPSand DGPS processing system 42 which receives and/or derives positionalcorrections for positional data derived from the GPS signals to therebyimprove accuracy of the position of the object provided by the GPSpositioning system, for example, using signals from one or more of theDGPS satellites 30. A notification system, such as driver warning system45, is coupled to the correction unit and is designed to notify a personconcerned with the position of the object about the current position ofthe object. Navigation system 46 is coupled to the correction unit forreceiving and acting upon the accurate positional information of theobject provided by the correction unit, and as shown, is integrated intothe common system 50. The optional map database 48 is coupled to thenavigation system 46 which may then receive information about a travellane the vehicle is traveling on and guide an operator of the vehiclebased on the accurate positional information and travel laneinformation. In this case, the warning system would notify an operatorof the vehicle of the position of the vehicle to prevent accidentsinvolving the vehicle. In one embodiment, a display displays theposition of the vehicle on a map along with the position of othervehicles to the driver or other personnel interested in the traffic onroads.

The correction unit 42 may be designed to communicate with satellites toreceive positional corrections therefrom and/or with ground basestations to receive positional corrections therefrom. As discussed belowwith reference to FIG. 5, a system for communicating with other vehicles(intra-vehicle communication 56) may be provided to transmit GPS signalsand/or positional corrections to the other vehicles and/or receive GPSsignals and/or positional corrections from the other vehicles.

10.8 Accident Avoidance

FIG. 5 is a block diagram of the more advanced accident avoidance systemof this invention and method of the present invention illustratingsystem sensors, transceivers, computers, displays, input and outputdevices and other key elements.

As illustrated in FIG. 5, the vehicle accident avoidance system isimplemented using a variety of microprocessors and electronic circuits100 to interconnect and route various signals between and among theillustrated subsystems. GPS receiver 52 is used to receive GPS radiosignals as illustrated in FIG. 1. DGPS receiver 54 receives thedifferential correction signals from one or more base stations eitherdirectly or via a geocentric stationary or LEO satellite, an earth-basedstation or other means. Inter-vehicle communication subsystem 56 is usedto transmit and receive information between various nearby vehicles.This communication will in general take place via broadband orultra-broadband communication techniques, or on dedicated frequencyradio channels, or in a preferred mode, noise communication system asdescribed above. This communication may be implemented using multipleaccess communication methods including frequency division multipleaccess (FDMA), timed division multiple access (TDMA), or code divisionmultiple access (CDMA), or noise communication system, in a manner topermit simultaneous communication with and between vehicles. Other formsof communication between vehicles are possible such as through theInternet. This communication may include such information as the preciselocation of a vehicle, the latest received signals from the GPSsatellites in view, other road condition information, emergency signals,hazard warnings, vehicle velocity and intended path, and any otherinformation which is useful to improve the safety of the vehicle roadsystem.

Infrastructure communication system 58 permits bi-directionalcommunication between the host vehicle and the infrastructure andincludes such information transfer as updates to the digital maps,weather information, road condition information, hazard information,congestion information, temporary signs and warnings, and any otherinformation which can improve the safety of the vehicle highway system.

Cameras 60 are used generally for interrogating environment nearby thehost vehicle for such functions as blind spot monitoring, backupwarnings, anticipatory crash sensing, visibility determination, lanefollowing, and any other visual information which is desirable forimproving the safety of the vehicle highway system. Generally, thecameras will be sensitive to infrared and/or visible light, however, insome cases a passive infrared camera will the used to detect thepresence of animate bodies such as deer or people on the roadway infront of the vehicle. Frequently, infrared or visible illumination willbe provided by the host vehicle. In the preferred system, highbrightness eye-safe IR will be used.

Radar 62 is primarily used to scan an environment close to and furtherfrom the vehicle than the range of the cameras and to provide an initialwarning of potential obstacles in the path of the vehicle. The radar 62can also be used when conditions of a reduced visibility are present toprovide advance warning to the vehicle of obstacles hidden by rain, fog,snow etc. Pulsed, continuous wave, noise or micropower impulse radarsystems can be used as appropriate. Also, Doppler radar principles canbe used to determine the object to host vehicle relative velocity.

Laser or terahertz radar 64 is primarily used to illuminate potentialhazardous objects in the path of the vehicle. Since the vehicle will beoperating on accurate mapped roads, the precise location of objectsdiscovered by the radar or camera systems can be determined using rangegating and scanning laser radar as described above or by phasetechniques.

The driver warning system 66 provides visual and/or audible warningmessages to the driver or others that a hazard exists. In addition toactivating a warning system within the vehicle, this system can activatesound and/or light systems to warn other people, animals, or vehicles ofa pending hazardous condition. In such cases, the warning system couldactivate the vehicle headlights, tail lights, horn and/or thevehicle-to-vehicle, Internet or infrastructure communication system toinform other vehicles, a traffic control station or other base station.This system will be important during the early stages of implementationof RtZF®, however as more and more vehicles are equipped with thesystem, there will be less need to warn the driver or others ofpotential problems.

Map database subsystem 68, which could reside on an external memorymodule, will contain all of the map information such as road edges up to2 cm accuracy, the locations of stop signs, stoplights, lane markersetc. as described above. The fundamental map data can be organized onread-only magnetic or optical memory with a read/write associated memoryfor storing map update information. Alternatively, the map informationcan be stored on rewritable media that can be updated with informationfrom the infrastructure communication subsystem 58. This updating cantake place while the vehicle is being operated or, alternatively, whilethe vehicle is parked in a garage or on the street.

Three servos are provided for controlling the vehicle during the laterstages of implementation of the RtZF® product and include a brake servo70, a steering servo 72, and a throttle servo 74. The vehicle can becontrolled using deterministic, fuzzy logic, neural network or,preferably, neural-fuzzy algorithms.

As a check on the inertial system, a velocity sensor 76 based on a wheelspeed sensor, or ground speed monitoring system using lasers, radar orultrasonics, for example, can be provided for the system. A radarvelocity meter is a device which transmits a noise modulated radar pulsetoward the ground at an angle to the vertical and measures the Dopplervelocity of the returned signal to provide an accurate measure of thevehicle velocity relative to the ground. Another radar device can bedesigned which measures the displacement of the vehicle. Othermodulation techniques and other radar systems can be used to achievesimilar results. Other systems are preferably used for this purpose suchas the GPS/DGPS or precise position systems.

The inertial navigation system (INS), sometimes called the inertialreference unit or IRU, comprises one or more accelerometers 78 and oneor more gyroscopes 80. Usually, three accelerometers would be requiredto provide the vehicle acceleration in the latitude, longitude andvertical directions and three gyroscopes would be required to providethe angular rate about the pitch, yaw and roll axes. In general, agyroscope would measure the angular rate or angular velocity. Angularacceleration may be obtained by differentiating the angular rate.

A gyroscope 80, as used herein in the IRU, includes all kinds ofgyroscopes such as MEMS-based gyroscopes, fiber optic gyroscopes (FOG)and accelerometer-based gyroscopes.

Accelerometer-based gyroscopes encompass a situation where twoaccelerometers are placed apart and the difference in the accelerationis used to determine angular acceleration and a situation where anaccelerometer is placed on a vibrating structure and the Coriolis effectis used to obtain the angular velocity.

The possibility of an accelerometer-based gyroscope 80 in the IRU ismade possible by construction of a suitable gyroscope by InterstateElectronics Corporation (IEC). IEC manufactures IMUs in volume based onpSCIRAS (micro-machined Silicon Coriolis Inertial Rate and AccelerationSensor) accelerometers. Detailed information about this device can befound at the IEC website at iechome.com.

There are two ways to measure angular velocity (acceleration) usingaccelerometers. The first way involves installing the accelerometers ata distance from one another and calculating the angular velocity by thedifference of readings of the accelerometers using dependencies betweenthe centrifugal and tangential accelerations and the angularvelocity/acceleration. This way requires significant accuracy of theaccelerometers.

The second way is based on the measurement of the Coriolis accelerationthat arises when the mass of the sensing element moves at a relativelinear speed and the whole device performs a transportation rotationabout the perpendicular axis. This principle is a basis of allmechanical gyroscopes, including micromachined ones. The difference ofthis device is that the micromachined devices aggregate the linearoscillation excitation system and the Coriolis acceleration measurementsystem, while two separate devices are used in the proposed secondmethod. The source of linear oscillations is the mechanical vibrationsuspension, and the Coriolis acceleration sensors are the micromachinedaccelerometers. On one hand, the presence of two separate devices makesthe instrument bigger, but on the other hand, it enables the use of moreaccurate sensors to measure the Coriolis acceleration. In particular,compensating accelerometer systems could be used which are more accurateby an order of magnitude than open structures commonly used inmicromachined gyroscopes.

Significant issues involved in the construction of anaccelerometer-based gyroscope are providing a high sensitivity of thedevice, a system for measuring the suspension vibration, separating thesignals of angular speed and linear acceleration; filtering noise in theoutput signals of the device at the suspension frequency, providing acorrelation between errors in the channels of angular speed and linearacceleration, considering the effect of nonlinearity of theaccelerometers and the suspension on the error of the output signals.

A typical MEMS-based gyroscope uses a quartz tuning fork. The vibrationof the tuning fork, along with applied angular rotation (yaw rate of thecar), creates Coriolis acceleration on the tuning fork. An accelerometeror strain gage attached to the tuning fork measures the minute Coriolisforce. Signal output is proportional to the size of the tuning fork. Togenerate enough output signal, the tuning fork must vibrate forcefully.Often, this can be accomplished with a high Q structure. Manufacturersoften place the tuning fork in a vacuum to minimize mechanical dampingby air around the tuning fork. High Q structures can be fairly fragile.

The gyroscope often experiences shock and vibration because it must berigidly connected to the car to accurately measure yaw rate, forexample. This mechanical noise can introduce signals to the Coriolispick-off accelerometer that is several orders of magnitude higher thanthe tuning-fork-generated Coriolis signal. Separating the signal fromthe noise is not easy. Often, the shock or vibration saturates thecircuitry and makes the gyroscope output unreliable for a short time.

Conventional MEMS-based gyroscopes are usually bulky (100 cm³ or more isnot uncommon). This is partly the result of the addition of mechanicalantivibration mounts, which are incorporated to minimize sensitivity toexternal vibration.

New MEMS-based gyroscopes avoid these shortcomings, though. For example,Analog Devices' iMEMS gyro is expected to be 7 by 7 by 3 mm (0.15 cm³).Rather than quartz, it uses a resonating polysilicon beam structure,which creates the velocity element that produces the Coriolis force whenangular rate is presented to it. At the outer edges of the polysiliconbeam, orthogonal to the resonating motion, a capacitive accelerometermeasures the Coriolis force. The gyroscope has two sets of beams inantiphase that are placed next to each other, and their outputs are readdifferentially, attenuating external vibration sensitivity.

An accelerometer 78, as used herein in the IRU, includes conventionalpiezoelectric-based accelerometers, MEMS-based accelerometers (such asmade by Analog Devices) and the type as described in U.S. Pat. No.6,182,509 entitled “Accelerometer without proof mass”.

Display subsystem 82 includes an appropriate display driver and either aheads-up or other display system for providing system information to thevehicle operator. Display subsystem 82 may include multiple displays fora single occupant or for multiple occupants, e.g., directed towardmultiple seating positions in the vehicle. One type of display may be adisplay made from organic light emitting diodes (OLEDs). Such a displaycan be sandwiched between the layers of glass that make up thewindshield and does not require a projection system.

The information being displayed on the display can be in the form ofnon-critical information such as the location of the vehicle on a map,as selected by the vehicle operator and/or it can include warning orother emergency messages provided by the vehicle subsystems or fromcommunication with other vehicles or the infrastructure. An emergencymessage that the road has been washed out ahead, for example, would bean example of such a message.

Generally, the display will make use of icons when the position of thehost vehicle relative to obstacles or other vehicles is displayed.Occasionally, as the image can be displayed especially when the objectcannot be identified. Icons can be selected which are representative ofthe transmitters from which wireless signals are received.

A general memory unit 84 which can comprise read-only memory or randomaccess memory or any combination thereof, is shown. This memory module,which can be either located at one place or distributed throughout thesystem, supplies the information storage capability for the system.

For advanced RtZF® systems containing the precise positioningcapability, subsystem 86 provides the capability of sending andreceiving information to infrastructure-based precise positioning tagsor devices which may be based on noise or micropower impulse radartechnology, IR lasers, radar or IR reflector (e.g. corner cube ordihedral) or RFIR technology or equivalent. Once again the PPS systemcan also be based on a signature analysis using the adaptive associativememory technology or equivalent.

In some locations where weather conditions can deteriorate and degraderoad surface conditions, various infrastructure-based sensors can beplaced either in or adjacent to the road surface. Subsystem 88 isdesigned to interrogate and obtained information from such road-basedsystems. An example of such a system would be an RFID tag containing atemperature sensor. This device may be battery-powered or, preferably,would receive its power from energy harvesting (e.g., solar energy,vibratory energy), the vehicle-mounted interrogator, or other hostvehicle-mounted source, as the vehicle passes nearby the device. In thismanner, the vehicle can obtain the temperature of the road surface andreceive advanced warning when the temperature is approaching conditionswhich could cause icing of the roadway, for example. An RFID based on asurface acoustic wave (SAW) device is one preferred example of such asensor, see U.S. Pat. No. 6,662,642. An infrared sensor on the vehiclecan also be used to determine the road temperature and the existence ofice or snow.

In order to completely eliminate automobile accidents, a diagnosticsystem is required on the vehicle that will provide advanced warning ofany potential vehicle component failures. Such a system is described inU.S. Pat. No. 5,809,437 (Breed).

For some implementations of the RtZF® system, stoplights will be fittedwith transmitters which will broadcast a signal when the light is red.Such a system could make use of the vehicle noise communication systemas described above. This signal can be then received by a vehicle thatis approaching the stoplight provided that vehicle has the proper sensoras shown as 92. Alternatively, a camera can be aimed in the direction ofstoplights and, since the existence of the stoplight will be known bythe system, as it will have been recorded on the map, the vehicle willknow when to look for a stoplight and determine the color of the light.

An alternative idea is for the vehicle to broadcast a signal to thestoplight if, via a camera or other means, it determines that the lightis red. If there are no vehicles coming from the other direction, thelight can change permitting the vehicle to proceed without stopping.Similarly, if the stoplight has a camera, it can look in all directionsand control the light color depending on the number of vehiclesapproaching from each direction. A system of phasing vehicles can alsobe devised whereby the speed of approaching vehicles is controlled sothat they interleave through the intersection and the stoplight may notbe necessary.

Although atomic clocks are probably too expensive to the deployed onautomobiles, nevertheless there has been significant advances recentlyin the accuracy of clocks to the extent that it is now feasible to placea reasonably accurate clock as a subsystem 94 to this system. Since theclock can be recalibrated from each DGPS transmission, the clock driftcan be accurately measured and used to predict the precise time eventhough the clock by itself may be incapable of doing so. To the extentthat the vehicle contains an accurate time source, the satellites inview requirement can temporarily drop from 4 to 3. An accurate clockalso facilitates the carrier phase DGPS implementations of the system asdiscussed above. Additionally, as long as a vehicle knows approximatelywhere it is on the roadway, it will know its altitude from the map andthus one less satellite is necessary.

Power is supplied to the system as shown by power subsystem 96. Certainoperator controls are also permitted as illustrated in subsystem 98.

The control processor or central processor and circuit board subsystem100 to which all of the above components 52-98 are coupled, performssuch functions as GPS ranging, DGPS corrections, image analysis, radaranalysis, laser radar scanning control and analysis of receivedinformation, warning message generation, map communication, vehiclecontrol, inertial navigation system calibrations and control, displaycontrol, precise positioning calculations, road condition predictions,and all other functions needed for the system to operate according todesign.

A display could be provided for generating and displaying warningmessages which is visible to the driver and/or passengers of thevehicle. The warning could also be in the form of an audible tone, asimulated rumble strip and light and other similar ways to attract theattention of the driver and/or passengers. Although vibration systemshave been proposed by others, the inventors have found that a pure noiserumble strip is preferred and is simpler and less costly to implement.

Vehicle control also encompasses control over the vehicle to preventaccidents. By considering information from the map database 48, from thenavigation system 46, and the position of the vehicle obtained via GPS,DGPS and PPS systems, a determination can be made whether the vehicle isabout to run off the road, cross a yellow line and run a stop sign, aswell as the existence or foreseen occurrence of other potential crashsituations. The color of an approaching stoplight can also be factoredin the vehicle control as can information from the vehicle to vehicle,vehicle to infrastructure and around vehicle radar, visual or IRmonitoring systems.

FIG. 5A shows a selected reduced embodiment of the accident avoidancesystem shown in FIG. 5. The system includes an inertial reference unitincluding a plurality of accelerometers and gyroscopes, namelyaccelerometers 78A, preferably three of any type disclosed above, andgyroscopes 80A, preferably three of any type disclosed above. Anaccurate clock 94A is provided to obtain a time base or time reference.This system will accurately determine the motion (displacement,acceleration and/or velocity) of the vehicle in 6 degrees of freedom (3displacements (longitudinal, lateral and vertical)) via theaccelerometers 78A and three rotations (pitch, yaw and roll) via thegyroscopes 80A. As such, along with a time base from clock 94A, theprocessor 100A can determine that there was an accident and preciselywhat type of accident it was in terms of the motion of the vehicle(frontal, side, rear and rollover). This system is different from acrash sensor in that this system can reside in the passenger compartmentof the vehicle where it is protected from actually being in the accidentcrush and/or crash zones and thus it does not have to forecast theaccident severity. It knows the resulting vehicle motion and thereforeexactly what the accident was and what the injury potential is. Atypical crash sensor can get destroyed or at least rotated during thecrash and thus will not determine the real severity of the accident.

Processor 100A is coupled to the inertial reference unit and also iscapable of performing the functions of vehicle control, such as viacontrol of the brake system 70A, steering system 72A and throttle system74A, crash sensing, rollover sensing, cassis control sensing, navigationfunctions and accident prevention as discussed herein.

Preferably, a Kalman filter is used to optimize the data from theinertial reference unit as well as other input sources of data, signalsor information. Also, a neural network, fuzzy logic or neural-fuzzysystem could be used to reduce the data obtained from the varioussensors to a manageable and optimal set. The actual manner in which aKalman filter can be constructed and used in the invention would be leftto one skilled in the art. Note that in the system of the inventionsdisclosed herein, the extensive calibration process carried on by othersuppliers of inertial sensors is not required since the systemperiodically corrects the errors in the sensors and revises thecalibration equation. This in some cases can reduce the manufacturingcost on the IMU by a factor of ten.

Further, the information from the accelerometers 78A and gyroscopes 80Ain conjunction with the time base or reference is transmittable via thecommunication system 56A,58A to other vehicles, possibly for the purposeof enabling other vehicles to avoid accidents with the host vehicle,and/or to infrastructure.

One particularly useful function would be for the processor to send datafrom, or data derived from, the accelerometers and gyroscopes relatingto a crash, i.e., indicative of the severity of the accident with thepotential for injury to occupants, to a monitoring location for thedispatch of emergency response personnel, i.e., an EMS facility or firestation. Other telematics functions could also be provided.

10.9 Exterior Surveillance System

FIG. 6 is a block diagram of the host vehicle exterior surveillancesystem. Cameras 60 are primarily intended for observing the immediateenvironment of the vehicle. They are used for recognizing objects thatcould be most threatening to the vehicle, i.e., closest to the vehicle.These objects include vehicles or other objects that are in the vehicleblind spot, objects or vehicles that are about to impact the hostvehicle from any direction, and objects either in front of or behind thehost vehicle which the host vehicle is about to impact. These functionsare normally called blind spot monitoring and collision anticipatorysensors.

As discussed above, the cameras 60 can use naturally occurring visibleor infrared radiation (particularly eye-safe IR), or other parts of theelectromagnetic spectrum including terahertz and x-rays, or they may besupplemented with sources of visible or infrared illumination from thehost vehicle. Note that there generally is little naturally occurringterahertz radiation other than the amount that occurs in black bodyradiation from all sources. The cameras 60 used are preferably highdynamic range cameras that have a dynamic range exceeding 60 db andpreferably exceeding 100 db. Such commercially available cameras includethose manufactured by the Photobit Corporation in California and the IMSChips Company in Stuttgart Germany. Alternately, various other meansexist for increasing the effective dynamic range through shutter controlor illumination control using a Kerr or Pokel cell, modulatedillumination, external pixel integration etc.

These cameras are based on CMOS technology and can have the importantproperty that pixels are independently addressable. Thus, the controlprocessor may decide which pixels are to be read at a particular time.This permits the system to concentrate on certain objects of interestand thereby make more effective use of the available bandwidth.

Video processor printed circuit boards or feature extractor 61 can belocated adjacent and coupled to the cameras 60 so as to reduce theinformation transferred to the control processor. The video processorboards or feature extractor 61 can also perform the function of featureextraction so that all values of all pixels do not need to be sent tothe neural network for identification processing. The feature extractionincludes such tasks as determining the edges of objects in the sceneand, in particular, comparing and subtracting one scene from another toeliminate unimportant background images and to concentrate on thoseobjects which had been illuminated with infrared or terahertz radiation,for example, from the host vehicle. By these and other techniques, theamount of information to be transferred to the neural network issubstantially reduced.

The neural network 63 receives the feature data extracted from thecamera images by the video processor feature extractor 61 and uses thisdata to determine the identification of the object in the image. Theneural network 63 has been previously trained on a library of imagesthat can involve as many as one million such images. Fortunately, theimages seen from one vehicle are substantially the same as those seenfrom another vehicle and thus the neural network 63 in general does notneed to be trained for each type of host vehicle.

As the number of image types increases, modular or combination neuralnetworks can be used to simplify the system.

Although the neural network 63 has in particular been described, otherpattern recognition techniques are also applicable. One such techniqueuses the Fourier transform of the image and utilizes either opticalcorrelation techniques or a neural network trained on the Fouriertransforms of the images rather than on the image itself. In one case,the optical correlation is accomplished purely optically wherein theFourier transform of the image is accomplished using diffractiontechniques and projected onto a display, such as a garnet crystaldisplay, while a library of the object Fourier transforms is alsodisplayed on the display. By comparing the total light passing throughthe display, an optical correlation can be obtained very rapidly.Although such a technique has been applied to scene scanning by militaryhelicopters, it has previously not been used in automotive applications.

The laser radar system 64 is typically used in conjunction with ascanner 65. The scanner 65 typically includes two oscillating mirrors,or a MEMS mirror capable of oscillating in two dimensions, which causethe laser light to scan the two dimensional angular field. Alternately,the scanner can be a solid-state device utilizing a crystal having ahigh index of refraction which is driven by an ultrasonic vibrator asdiscussed above or rotating mirrors. The ultrasonic vibrator establisheselastic waves in the crystal which diffracts and changes the directionof the laser light. Another method is to use the DLP technology fromTexas Instruments. This technology allows more than 1 million MEMSmirrors to control the direction of the laser light.

The laser beam can be frequency, amplitude, time, code or noisemodulated so that the distance to the object reflecting the light can bedetermined. The laser light strikes an object and is reflected backwhere it can be guided onto a pin diode, or other high speed photodetector. Since the direction of laser light is known, the angularlocation of the reflected object is also known and since the laser lightis modulated the distance to the reflected point can be determined. Byvarying modulation frequency of the laser light, or through noise orcode modulation, the distance can be very precisely measured.

Alternatively, the time-of-flight of a short burst of laser light can bemeasured providing a direct reading of the distance to the object thatreflected the light. By either technique, a three-dimensional map can bemade of the surface of the reflecting object. Objects within a certainrange of the host vehicle can be easily separated out using the rangeinformation. This can be done electronically using a technique calledrange gating, or it can be accomplished mathematically based on therange data. By this technique, an image of an object can be easilyseparated from other objects based on distance from the host vehicle.

Since the vehicle knows its position accurately and in particular itknows the lane on which it is driving, a determination can be made ofthe location of any reflective object and in particular whether or notthe reflective object is on the same lane as the host vehicle. This factcan be determined since the host vehicle has a map and the reflectiveobject can be virtually placed on that map to determine its location onthe roadway, for example.

The laser radar system will generally operate in the near-infrared partof the electromagnetic spectrum and preferably in the eye-safe part. Thelaser beam will be of relatively high intensity compared to thesurrounding radiation and thus even in conditions of fog, snow, andheavy rain, the penetration of the laser beam and its reflection willpermit somewhat greater distance observations than the human driver canperceive. Under the RtZF® plan, it is recommended that the speed of thehost vehicle be limited such that vehicle can come to a complete stop inone half or less of the visibility distance. This will permit the laserradar system to observe and identify threatening objects that are beyondthe visibility distance, apply the brakes to the vehicle if necessarycausing the vehicle to stop prior to an impact, providing an addeddegree of safety to the host vehicle.

Radar system 62 is mainly provided to supplement laser radar system. Itis particularly useful for low visibility situations where thepenetration of the laser radar system is limited. The radar system,which is most probably a noise or pseudonoise modulated continuous waveradar, can also be used to provide a crude map of objects surroundingthe vehicle. The most common use for automotive radar systems is foradaptive cruise control systems where the radar monitors the distanceand, in some cases, the velocity of the vehicle immediately in front ofthe host vehicle. The radar system 62 is controlled by the controlprocessor 100.

Display system 82 was discussed previously and can be either a heads upor other appropriate display.

Control processor 100 can be attached to a vehicle special or generalpurpose bus 110 for transferring other information to and from thecontrol processor to other vehicle subsystems.

In interrogating other vehicles on the roadway, a positiveidentification of the vehicle and thus its expected properties such asits size and mass can sometimes be accomplished by laser vibrometry. Bythis method, a reflected electromagnetic wave can be modulated based onthe vibration that the vehicle is undergoing. Since this vibration iscaused at least partially by the engine, and each class of engine has adifferent vibration signature, this information can be used to identifythe engine type and thus the vehicle. This technique is similar to oneused to identify enemy military vehicles by the U.S. military. It isalso used to identify ships at sea using hydrophones. In the presentcase, a laser beam is directed at the vehicle of interest and thereturned reflected beam is analyzed such as with a Fourier transform todetermine the frequency makeup of the beam. This can then be related toa vehicle to identify its type either through the use of a look-up tableor neural network or other appropriate method. This information can thenbe used as information in connection with an anticipatory sensor as itwould permit a more accurate estimation of the mass of a potentiallyimpacting vehicle.

Once the vehicle knows where it is located, this information can bedisplayed on a heads-up display and if an occupant sensor has determinedthe location of the eyes of the driver, the road edges, for example, andother pertinent information from the map database can be displayedexactly where they would be seen by the driver. For the case of drivingin dense fog or on a snow covered road, the driver will be able to seethe road edges perhaps exactly or even better than the real view, insome cases. Additionally, other information gleaned by the exteriormonitoring system can show the operator the presence of other vehiclesand whether they represent a threat to the host vehicle (see for example“Seeing the road ahead”, GPS World Nov. 1, 2003, which describes asystem incorporating many of the current assignee's ideas describedherein).

10.10 Corridors

FIG. 7 shows an implementation of the invention in which a vehicle 18 istraveling on a roadway in a defined corridor in the direction X. Eachcorridor is defined by lines 14. If the vehicle is traveling in onecorridor and strays in the direction Y so that it moves along the line22, e.g., the driver is falling asleep, the system on board the vehiclein accordance with the invention will activate a warning. Morespecifically, the system continually detects the position of thevehicle, such as by means of the GPS, DGPS and/or PPS, and has thelocations of the lines 14 defining the corridor recorded in its mapdatabase. Upon an intersection of the position of the vehicle and one ofthe lines 14 as determined by a processor, the system may be designed tosound an alarm to alert the driver to the deviation or possibly evencorrect the steering of the vehicle to return the vehicle to within thecorridor defined by lines 14.

FIG. 8 shows an implementation of the invention in which a pair ofvehicles 18, 26 is traveling on a roadway each in a defined corridordefined by lines 14 and each is equipped with a system in accordancewith the invention. The system in each vehicle 18, 26 will receive datainforming it of the position of the other vehicle and prevent accidentsfrom occurring, e.g., if vehicle 18 moves in the direction of arrow 20.This can be accomplished via direct wireless broadband communication orany of the other communication methods described above, or throughanother path such as via the Internet or through a base station, whereineach vehicle transmits its best estimate of its absolute location on theearth along with an estimate of the accuracy of this location. If onevehicle has recently passed a precise positioning station, for example,then it will know its position very accurately to within a fewcentimeters. Each vehicle can also send the latest satellite messages,or a portion thereof or data derived therefrom, that it received,permitting each vehicle to precisely determine its relative location tothe other since the errors in the signals will be the same for bothvehicles. To the extent that both vehicles are near each other, even thecarrier phase ambiguity can be determined and each vehicle will know itsposition relative to the other to within better than a few centimeters.As more and more vehicles become part of the community and communicatetheir information to each other, each vehicle can even more accuratelydetermine its absolute position and especially if one vehicle knows itsposition very accurately, if it recently passed a PPS for example, thenall vehicles will know their position with approximately the sameaccuracy and that accuracy will be able to be maintained for as long asa vehicle keeps its lock on the satellites in view. If that lock is losttemporarily, the INS system will fill in the gaps and, depending on theaccuracy of that system, the approximate 2 centimeter accuracy can bemaintained even if the satellite lock is lost for up to approximatelyfive minutes.

A five minute loss of satellite lock is unlikely except in tunnels or inlocations where buildings or geological features interfere with thesignals. In the building case, the problem can be eliminated through theplacement of PPS stations, or through environmental signature analysis,and the same would be true for the geological obstruction case except inremote areas where ultra precise positioning accuracy is probably notrequired. In the case of tunnels, for example, the cost of adding PPSstations is insignificant compared with the cost of building andmaintaining the tunnel.

10.11 Vehicle Control

FIG. 12 a is a flow chart of the method in accordance with theinvention. The absolute position of the vehicle is determined at 130,e.g., using a GPS, DGPS, PPS system, and compared to the edges of theroadway at 134, which is obtained from a memory unit 132. Based on thecomparison at 134, it is determined whether the absolute position of thevehicle is approaching close to or intersects an edge of the roadway at136. If not, then the position of the vehicle is again obtained, e.g.,at a set time interval thereafter, and the process continues. If yes, analarm and/or warning system will be activated and/or the system willtake control of the vehicle (at 140) to guide it to a shoulder of theroadway or other safe location.

FIG. 12 b is another flow chart of the method in accordance with theinvention similar to FIG. 12 a. Again the absolute position of thevehicle is determined at 130, e.g., using a GPS, DGPS, PPS system, andcompared to the location of a roadway yellow line at 142 (or possiblyanother line which indicates an edge of a lane of a roadway), which isobtained from a memory unit 132. Based on the comparison at 144, it isdetermined whether the absolute position of the vehicle is approachingclose to or intersects the yellow line 144. If not, then the position ofthe vehicle is again obtained, e.g., at a set time interval thereafter,and the process continues. If yes, an alarm will sound and/or the systemwill take control of the vehicle (at 146) to control the steering orguide it to a shoulder of the roadway or other safe location.

FIG. 12 c is another flow chart of the method in accordance with theinvention similar to FIG. 12 a. Again the absolute position of thevehicle is determined at 130, e.g., using a GPS, DGPS, PPS system, andcompared to the location of a roadway stoplight at 150, which isobtained from a memory unit 132. Based on the comparison at 150, it isdetermined whether the absolute position of the vehicle is approachingclose to a stoplight. If not, then the position of the vehicle is againobtained, e.g., at a set interval thereafter, and the process continues.If yes, a sensor determines whether the stoplight is red (e.g., acamera, transmission from stoplight) and if so, an alarm will soundand/or the system will take control of the vehicle (at 154) to controlthe brakes or guide it to a shoulder of the roadway or other safelocation. A similar flow chart can be now drawn by those skilled in theart for other conditions such as stop signs, vehicle speed control,collision avoidance etc.

10.12 Intersection Collision Avoidance

FIG. 13 illustrates an intersection of a major road 170 with a lesserroad 172. The road 170 has the right of way and stop signs 174 have beenplaced to control the traffic on the lesser road 172. Vehicles 18 and 26are proceeding on road 172 and vehicle 25 is proceeding on road 170. Avery common accident is caused when vehicle 18 ignores the stop sign 174and proceeds into the intersection where it is struck on the side byvehicle 25 or strikes vehicle 25 on the side.

Using the teachings of this invention, vehicle 18 will know of theexistence of the stop sign and if the operator attempts to proceedwithout stopping, the system will sound a warning and if that warning isnot heeded, the system will automatically bring the vehicle 18 to astop, preventing it from intruding into the intersection.

Another common accident is where vehicle 18 does in fact stop but thenproceeds forward without noticing vehicle 25 thereby causing anaccident. Since in the fully deployed RtZF® system, vehicle 18 will knowthrough the vehicle-to-vehicle communication the existence and locationof vehicle 25 and can calculate its velocity, the system can once againtake control of vehicle 18 if a warning is not heeded and preventvehicle 18 from proceeding into the intersection and thereby prevent theaccident.

In the event that the vehicle 25 is not equipped with the RtZF® system,vehicle 18 will still sense the presence of vehicle 25 through the laserradar, radar and camera systems. Once again, when the position andvelocity of vehicle 25 is sensed, appropriate action can be taken by thesystem in vehicle 18 to eliminate the accident.

In another scenario where vehicle 18 properly stops at the stop sign,but vehicle 26 proceeds without observing the presence of the stoppedvehicle 18, the laser radar, radar and camera systems will all operateto warn the driver of vehicle 26 and if that warning is not heeded, thesystem in vehicle 26 will automatically stop the vehicle 26 prior to itsimpacting vehicle 18. Thus, in the scenarios described above the “Roadto Zero Fatalities”® system and method of this invention will preventcommon intersection accidents from occurring.

FIG. 14 is a view of an intersection where traffic is controlled bystoplights 180. If the vehicle 18 does not respond in time to a redstoplight, the system as described above will issue a warning and if notheeded, the system will take control of the vehicle 18 to prevent itfrom entering the intersection and colliding vehicle 25. In this case,the stoplight 180 will emit a signal indicating its color, such as byway of the communication system, and/or vehicle 18 will have a cameramounted such that it can observe the color of the stoplight. There areof course other information transfer methods such as through theInternet. In this case, buildings 182 obstruct the view from vehicle 18to vehicle 25 thus an accident can still be prevented even when theoperators are not able to visually see the threatening vehicle. If bothvehicles have the RtZF® system they will be communicating and theirpresence and relative positions will be known to both vehicles.

FIG. 15 illustrates the case where vehicle 18 is about to execute aleft-hand turn into the path of vehicle 25. This accident will beprevented if both cars have the RtZF® system since the locations andvelocities of both vehicles 18, 25 will be known to each other. Ifvehicle 25 is not equipped and vehicle 18 is, then the camera, radar,and laser radar subsystems will operate to prevent vehicle 18 fromturning into the path of vehicle 25. Once again common intersectionaccidents are prevented by this invention.

The systems described above can be augmented by infrastructure-basedsensing and warning systems. Camera, laser or terahertz radar or radarsubsystems such as placed on the vehicle can also be placed atintersections to warn the oncoming traffic if a collision is likely tooccur. Additionally, simple sensors that sense the signals emitted byoncoming vehicles, including radar, thermal radiation, etc., can be usedto operate warning systems that notify oncoming traffic of potentiallydangerous situations. Thus, many of the teachings of this invention canbe applied to infrastructure-based installations in addition to thevehicle-resident systems.

Although FIGS. 13-15 appear to show a typical intersection for landvehicles such as cars, trucks and buses, the same techniques to avoidcollisions at intersections are also applicable for other types ofvehicles, including airplane, boats, ships, off-road vehicles and thelike.

10.13 Privacy

People do not necessarily want the government to know where they aregoing and therefore will not want information to be transmitted that canidentify the vehicle. The importance of this issue may be overestimated.Most people will not object to this minor infraction if they can get totheir destination more efficiently and safely.

On the other hand, it has been estimated that there are 100,000 vehicleson the road, many of them stolen, where the operators do not want thevehicle to be identified. If an identification process that positivelyidentifies the vehicle were made part of this system, it could thus cutdown on vehicle theft. Alternately, thieves might attempt to disconnectthe system thereby defeating the full implementation of the system andthus increasing the danger on the roadways and defeating the RtZF®objective. The state of the system would therefore need to beself-diagnosed and system readiness should be a condition for entry ontothe restricted lanes.

11. Other Features

11.1 Incapacitated Driver

As discussed herein, the RtZF® system of this invention also handles theproblem of the incapacitated driver thus eliminating the need for sleepsensors that appear in numerous U.S. patents. Such systems have not beenimplemented because of their poor reliability. The RtZF® system sensesthe result of the actions of the operator, which could occur for avariety of reasons including inattentiveness cause by cell phone use,old age, drunkenness, heart attacks, drugs as well as falling asleep.

11.2 Emergencies—Car Jacking, Crime

Another enhancement that is also available is to prevent car jacking inwhich case, the RtZF® system can function like the Lojack™ system. Inthe case where a car-jacking occurs, the location of the vehicle can bemonitored and if an emergency button is pushed, the location of thevehicle with the vehicle ID can be transmitted.

11.3 Headlight Dimmer

The system also solves the automatic headlight dimmer problem. Since theRtZF® system equipped vehicle knows where all other RtZF® systemequipped vehicles are located in its vicinity, it knows when to dim theheadlights. Since it is also interrogating the environment in front ofthe vehicle, it also knows the existence and approximate location of allnon-RtZF® system equipped vehicles. This is one example of a futureimprovement to the system. The RtZF® system is a system which lendsitself to continuous improvement without having to change systems on anexisting vehicle.

11.4 Rollover

It should be obvious from the above discussion that rollover accidentsshould be effectively eliminated by the RtZF® system. In the rare casewhere one does occur, the RtZF® system has the capability to sense thatevent since the location and orientation of the vehicle is known.

For large trucks that have varying inertial properties depending on theload that is being hauled, sensors can be placed on the vehicle thatmeasure angular and linear acceleration of a part of the vehicle. Sincethe geometry of the road is known, the inertial properties of thevehicle with load can be determined and thus the tendency of the vehicleto roll over can be determined. Since the road geometry is known thespeed of the truck can be limited based partially on its measuredinertial properties to prevent rollovers. The IMU can play a crucialrole here in that the motion of the vehicle is now accurately known to adegree previously not possible before the Kalman filter error correctionsystem was employed. This permits more precise knowledge and thus theability to predict the motion of the vehicle. The IMU can be input tothe chassis control system and, through appropriate algorithms, thethrottle, steering and brakes can be appropriately applied to prevent arollover. When the system described herein is deployed, rollovers shoulddisappear as the causes such as road ice, sharp curves and othervehicles are eliminated.

If a truck or other vehicle is driving on a known roadway where thevertical geometry (height and angle) has been previously determined andmeasured, then one or more accelerometers and gyroscopes can be placedat appropriate points on the truck and used to measure the response ofthe vehicle to the disturbance. From the known input and measuredresponse, the inertial properties (e.g. center of mass, massdistribution, moments of inertia, nature of load (e.g. shiftable orliquid)) of the vehicle can readily be determined by one skilled in theart. Similarly, if instead of a knowledge of the road from the mapdatabase, the input to the vehicle from the road can be measured byaccelerometers and gyroscopes placed on the chassis, for example, andthen the forcing function into the truck body is known and by measuringthe motion (accelerations and angular accelerations) the inertialproperties once again can be determined. Finally, the input from theroad can be treated statistically and again the inertial properties ofthe truck estimated. If a truck tractor is hauling a trailer then themeasuring devices can be placed at convenient locations of the trailersuch inside the trailer adjacent to the roof at the front and rear ofthe trailer.

If the map contains the information, then as the vehicle travels theroad and determines that there has been a change in the road propertiesthis fact can be communicated via telematics or other methods to the mapmaintenance personnel, for example. In this manner, the maps are keptcurrent and pothole or other evidence of road deterioration can be sentto appropriate personnel for attention.

Once the system determines that the vehicle is in danger or a rolloversituation, the operator can be notified with an audible or visualwarning (via a display or light) so that he or she can take correctiveaction. Additionally or alternately, the system can take control of thesituation and prevent the rollover through appropriate application ofbrakes (either on all wheels or selectively on particular wheels),throttle or steering.

11.5 Vehicle Enhancements

The RtZF® system can now be used to improve the accuracy of othervehicle-based instruments. The accuracy of the odometer and yaw ratesensors can be improved over time, for example, by regression, orthrough the use of a Kalman filter, against the DGPS data. The basicRtZF® system contains an IMU which comprises three accelerometers andthree gyroscopes. This system is always being updated by the DGPSsystem, odometer, vehicle speed sensor, magnetic field and field vectorsensors, PPS and other available sensors through a Kalman filter and insome cases a neural network.

11.6 Highway Enhancements

Enhancements to the roadways that result from the use of the RtZF®system include traffic control. The timing of the stoplights can now beautomatically adjusted based on the relative traffic flow. The positionof every vehicle within the vicinity of the light can be known from thecommunication system discussed above. When all vehicles have the RtZF®system, many stoplights will no longer be necessary since the flow oftraffic through an intersection can be accurately controlled to avoidcollisions.

Since the road conditions will now be known to the system, an enhancedRtZF® system will be able to advise an operator not to travel or,alternately, it can pick an alternate route if certain roads haveaccidents or have iced over, for example. Some people may decide notdrive if there is bad weather or congestion. The important point here isthat sensors will be available to sense the road condition as to bothtraffic and weather, this information will be available automaticallyand not require reporting from weather stations which usually have onlylate and inaccurate information. Additionally, pricing for the use ofcertain roads can be based on weather, congestion, time of day, etc.That is, pricing can by dynamically controlled.

The system lends itself to time and congestion-based allocation ofhighway facilities. A variable toll can automatically be charged tovehicles based on such considerations since the vehicle can beidentified. In fact, automatic toll systems now being implemented willlikely become obsolete as will all toll booths.

Finally, it is important to recognize that the RtZF® system is not a“sensor fusion” system. Sensor fusion is based on the theory that youcan take inputs from different sensors and combine them in such a way asto achieve more information from the combined sensors than from treatingthe sensor outputs independently in a deterministic manner. The ultimatesensor fusion system is based on artificial neural networks, sometimescombined with fuzzy logic to form a neural fuzzy system. Such systemsare probabilistic. Thus there will always be some percentage of caseswhere the decision reached by the network will be wrong. The use of suchsensor fusion, therefore, is inappropriate for the “Zero Fatalities”goal of the invention, although several of the sub-parts of the systemmay make use of neural networks and other pattern recognition methods.

11.7 Speed Control

Frequently a driver is proceeding down a road without knowing theallowed speed limit. This can happen if he or she recently entered aroad and a sign has not been observed or perhaps the driver just was notpaying attention or the sign was hidden from view by another vehicle. Ifthe allowed speed was represented in the map database, then it could bedisplayed on an in-vehicle display since the vehicle would know itslocation. Additionally, the allowable speed can be changed depending onweather conditions. In both cases, the speed of the vehicle can belimited to the permitted speed through the throttle control systemdiscussed above.

12. Hybrid Integrated Waveguide Transceiver of Automotive Radar with TwoAntennas

12.1 General Description of the Operation of Radar Transceiver with TwoAntennas

Referring first to FIG. 28, a block diagram of a transceiver operatingin the 76-77 GHz frequency range in accordance with the invention isshown. One intended use of this transceiver is as a front-end ofshort-range FMCW automotive radar. The circuit of this transceiverinvolves two separate antennas—transmit antenna 1 and receive antenna 2.Use of two separate antennas, which should be adequately isolated fromeach other, enables a considerable increase in transceiver potential andexcludes application of MM-wave isolators. The active MM-wave componentsof this transceiver operating at 76-77 GHz are highly efficientfrequency multiplier modules with high multiplication factor implementedon silicon IMPATT diodes. The main principles of construction of thisfrequency multiplier over the whole MM-wave range (30-300 GHz) aredisclosed in detail in the Russia Federation Patent No. 2,186,455 andU.S. patent application Ser. No. 10/473,280. Application of themultiplier circuit considerably improves transceiver operation stabilityrelative to output load.

To obtain optimal results, a reasonable compromise (as to structural andtechnological implementation) has been found when designing themicrowave elements of the transceiver. In a preferred embodiment of thepresent invention, all microwave elements of the frequency-settingsection operating at 7.6-7.7 GHz were made as a microstrip hybrid IC;only the components operating at 76-77 GHz had a waveguide design.Although the construction realized in this invention is the complex incomparison to other versions, a transceiver construction with twoseparate antennas and receivers with a double frequency conversionenables one to obtain the best transceiver specifications with respectto the transmitter power output and receiver noise factor.

The transceiver operates in the following manner. A saw-tooth voltageoscillator 3 forms symmetric saw-tooth voltage of 2.048 V and provides avoltage shift within 0-8 V. The saw-tooth voltage is formed digitally.This makes it possible to provide accuracy of amplitude level setting ofabout 0.001%. An oscillator 3 enables one to set such a period ofsaw-tooth voltage that is required for measurement of parameters, andprovides the required linearity of voltage variation during the wholesaw-tooth period. The saw-tooth voltage is applied to the varactorcontrol input of a transistor voltage-controlled oscillator (VCO) 4. Atthe VCO 4 output, a frequency-modulated (FM) signal (power of about 50mW in the 7.6-7.7 GHz frequency range, frequency tuning nonlinearity nomore than 0.01%) is formed. The VCO 4 employs a bipolar transistor,which makes it possible to obtain the minimal phase noise level for anoutput signal. Since such a VCO implementation is well known in the art,there is no need to describe it in detail. Then, this FM signal (withhigh linearity of frequency tuning) is divided into three parts with adivider (not shown in FIG. 28). One part of the VCO 4 signal is directedvia a first channel to the input of a transmitter active IMPATTmultiplier module 5, another part of the signal is directed via a secondchannel to the input of a heterodyne active IMPATT multiplier module 6,and the last part of the signal is directed via a third channel to theinput of a second balance mixer 9.

In this embodiment, the transceiver power source is the transmitteractive frequency multiplier module 5 (multiplication factor N=10) basedon a silicon IMPATT diode. The active IMPATT multiplier module 5provides formation of a radar probing signal with power no less than 30mW in the 76-77 GHz frequency range. The required linearity, frequencytuning rate and phase noise level for the radiated probing signal aredetermined by the parameters of the low-frequency VCO 4 operating at7.6-7.7 GHz. We have determined experimentally that increase of FM noiseduring multiplication with such a silicon IMPATT frequency multiplierdoes not exceed 20 logN at about 10-100 kHz offset from the carrier.High conversion efficiency of the active IMPATT multiplier module 5 (atmultiplication factor N=10) enables a single-stage multiplier circuit tobe realized. This makes the transceiver construction much simpler andreduces the number of elements in the circuit, thus making it morereliable and much less expensive. The output signal from the transmitteractive IMPATT multiplier module 5 is directed to the transmit antenna 1.

The receiver is made as a heterodyne circuit with double frequencyconversion. An echo-signal comes to a first balance mixer 7 via thereceive antenna 2. The power source of the first heterodyne is also theactive IMPATT frequency multiplier module 6 (with frequencymultiplication factor N=11) employing the same silicon IMPATT diode asin the transmitter IMPATT multiplier module 5. The heterodyne activeIMPATT multiplier module 6 provides the heterodyne power (required forthe first balance mixer 7) no less than 10 mW in the 83.6-84.7 GHzfrequency range. The required linearity, frequency tuning rate and phasenoise level for the radiated signal of the first heterodyne aredetermined by the parameters of the same low-frequency VCO 4 at 7.6-7.7GHz. The first intermediate frequency (IF) signal derived from theoutput of the first balance mixer 7 is amplified by a low-noise first IFamplifier 8. The second frequency conversion occurs in the secondbalance mixer 9. The second IF signal obtained at the output of thesecond balance mixer 9 is amplified by the second IF amplifier 10. Forthe second heterodyne, the signal from the low-frequency VCO 4 at7.6-7.7 GHz is used. This construction of the receiver provides thenoise factor of the receiver transmission line of 10-12 dB. Employingthe balance mixers in the receiver design provides the required degreeof suppression of the heterodyne amplitude modulated (AM) noise.

The signal reflected from the target and radiated probing signal ofsweeping frequency are mixed at balance mixers 7 and 9 to extract abeat-frequency signal that comes to the processing unit 11. Theprocessor 11 determines, with high accuracy, the distance to the targetfrom the results of analysis of the beat-frequency spectrum.

In a modified embodiment, the transceiver power source is thetransmitter active frequency multiplier module 5 wherein a highermultiplication factor (N=30) is used. In this case, the active IMPATTmultiplier module 5 provides formation of a radar probing signal withpower no less than 30 mW in the 76-77 GHz frequency range. The requiredlinearity, frequency tuning rate and phase noise level for the radiatedprobing signal are determined by the parameters of the low-frequency VCO4 operating at about 2.53-2.56 GHz, or even 2.5 GHz. It is likely thatan increase of FM noise during multiplication with such a silicon IMPATTfrequency multiplier does not exceed 20 logN at about 10-100 kHz offsetfrom the carrier. High conversion efficiency of the active IMPATTmultiplier module 5 (at multiplication factor N=30) enables asingle-stage multiplier circuit to be realized.

12.2 Transmitter Active IMPATT Multiplier Module

The transmitter active IMPATT frequency multiplier module 5 (whose blockdiagram is shown in FIG. 28) is a hybrid IC (HIC) involving an inputtransistor power amplifier 12 operating at 7.6-7.7 GHz, active IMPATTfrequency multiplier 13 (with frequency multiplication factor N=10)constructed on a silicon multiplying IMPATT diode 22 (see FIG. 29),bandpass filter 14, as well as voltage regulator 15 for transistors andDC bias current regulator 16 for the IMPATT diode 22. The transmittermodule 5 is located in a single metal housing with the coaxial input andwaveguide output (waveguide size WR-10). The supply voltages are appliedto the transmitter module 5 via feed-through insulators.

The FM signal at 7.6-7.7 GHz (power of 20 mW) from the VCO 4 enters theinput of the transistor power amplifier 12 via a coaxial connector. Thegain of the transistor power amplifier 12 operating at 7.6-7.7 GHz is+17 dB. Two balanced stages (connected in series) operate in thesaturation mode; they provide microwave power of 1 W at the output ofthe power amplifier 12. In a simple case, such an amplifier may berealized (as in a preferred embodiment of the invention) by utilizingmicrostrip technology in combination with GaAs field-effect transistors.It is apparent to those skilled in the art, however, that a monolithicor any other circuit with the same parameters (frequency range, gain andpower output) may be applied in construction of such an amplifier.

The output signal at 7.6-7.7 GHz from the transistor power amplifier 12enters the multiplying IMPATT diode 22 of the active IMPATT frequencymultiplier 13. The silicon IMPATT diode 22 (that was designed purposelyfor the 76-77 GHz frequency range) operates in the avalanche breakdownmode. To realize frequency multiplication, strong avalanche nonlinearity(of inductive nature) is used. High (13 dB) conversion efficiency isdetermined by the fact that this silicon IMPATT diode has negativeresistance at the required 10^(th) harmonic of input signal.

The silicon IMPATT diode 22 has a single-drift p⁺-n-n⁺ structure. It ismade using the traditional manufacturing technology [see, N. S.Boltovets, V. V. Basanets, V. N. Ivanov et al., Microwave diodes withcontact metallization systems based on silicides, nitrides and boridesof refractory metals, Semiconductor Physics, Quantum Electronics &Optoelectronics, 2000, vol. 3, no. 3, pp. 359-370]. The startingmaterial for production of the multiplying diode 22 may be a VPE-grownn-n⁺-Si wafer. During the process of epitaxy an n-Si layer (thickness of0.7 μm, impurity concentration of 3×10¹⁶ cm⁻³) is grown on alow-resistance (resistivity of 0.002 Ω×cm) As-doped n⁺-Si substrate.Typical technological processes (diffusion, chemical etching, vacuumsputtering, photolithography, plating of copper and gold, etc.) areapplied to make of a silicon wafer reverse diode mesas on an integralcopper heat sink (IMPATT diode chips) using the batch-fabricationtechnique. Then, the mesas are separated, and each IMPATT chip 30 ismounted on a gold-plated copper cylindrical heat sink base 31 inside adielectric bush 32 (see FIG. 30). The p⁺-contact of the IMPATT diode 22is connected to the gold-plated copper heat sink base 31, while then⁺-contact is connected to the metallized face of the dielectric bush 32via a gold multi-petal lead 33. The dielectric bush 32 is capped with agold-plated metal cap 34.

It should be noted that formation of a multiplying IMPATT diodeaccording to this invention is made using the standard manufacturingtechnology for silicon discrete microwave diodes and ICs; no developmentof additional specific technological processes is required. High degreeof maturity of silicon technologies (used for growing semiconductorsilicon material and production of devices on its basis) providesachieving reproducibly the required parameters at MM-wave frequenciesand makes it possible to realize them under mass production conditions.This fact, along with the advantages of the single-stage multiplicationcircuit implemented in a preferred embodiment of the invention, makesthe transceiver more reliable and less expensive.

It is known from S. M. Sze, Physics of Semiconductor Devices, SecondEdition, John Wiley & Sons, Inc., NewYork-Chichester-Brisbane-Toronto-Singapore (1981), Vol. 2, Chapter 10,that the operating frequency and efficiency of an IMPATT diode operationat that frequency are determined by the parameters of the diodestructure and mounting construction. Therefore a big number of the diodeparameters had to be optimized, such as the drift length (i.e., then-layer thickness), mesa cross section area, breakdown voltage, directcurrent density, capacitance and inductance of the mounting elements,etc. For silicon multiplying IMPATT diodes operating in the 76-77 GHzfrequency range the main parameter values after optimization are asfollows: impurity concentration in the n-layer of 3×10¹⁶ cm⁻³, n-layerthickness of 0.35 μm, mesa diameter of 40-50 μm, with the resonancefrequency in the 76-77 GHz range.

Considering the operation of the transmitter active IMPATT multipliermodule 5, taking into account FIGS. 28 and 29, matching between themultiplying IMPATT diode 22 and transistor amplifier 12 is performed bya microstrip board 26. The synchronizing signal from the transistorpower amplifier 12 goes via a microstrip line 28 segment to the siliconIMPATT diode 22. A DC bias is applied to the diode 22 from the currentregulator 16 via the above microstrip line 28 segment. The isolationbetween the IMPATT diode 22 DC bias voltage and the AC signal at 7.6-7.7GHz from the transistor power amplifier 12 is achieved due to a filter29 (included in the circuit of DC bias supply of the IMPATT diode 22)and a capacitance 27 (inserted in the break of the microstrip line 28).The IMPATT diode 22 is connected to the microstrip line 28 with agold-plated strap 25.

The silicon IMPATT diode 22 (operating in the avalanche breakdown modewhen its characteristic is nonlinear) converts the input synchronizingsignal to cause harmonics multiple to the input signal frequency toappear in the frequency spectrum. To separate the required 10^(th)harmonic of the input signal, the IMPATT diode 22 is placed within anoutput coupling circuit made as a T-shaped waveguide tee 23 (FIG. 29).Referring to FIG. 29, arranged in two opposite arms of the waveguide tee23 are tuning shorts 24, while the third arm of the waveguide tee 23serves for the microwave energy output. The waveguide tee 23 haswaveguide size WR-10. At the output of the waveguide tee 23, there is awaveguide bandpass filter 14 (see FIG. 28) whose pass band is 75.5-77.5GHz. Filter 14 efficiently suppresses the adjacent harmonics. Theproposed circuit provides maximal efficiency of the multiplying IMPATTdiode matching with both the microstrip line and waveguide transmissionline. In addition, it provides efficient heat removal from the diode andsupply of DC bias required for IMPATT diode operation. The circuit shownin FIG. 29 enables one to use the off-the-shelf discrete multiplyingIMPATT diodes, provides easy assembling of the transmitter module 5 andhigh mechanical strength of the module 5 as a whole. The output signal(at 76-77 GHz, power of 30-50 mW) from the transmitter active IMPATTmultiplier module 5 comes via the waveguide output to the transmitantenna 1.

12.3 Heterodyne Active IMPATT Multiplier Module

The active IMPATT multiplier module 6 of the first heterodyne of thereceiver is also a HIC involving an input transistor power amplifier 17operating at 7.6-7.7 GHz, active CW IMPATT frequency multiplier 18 (withmultiplication factor N=11) constructed on a silicon multiplying IMPATTdiode similar to the IMPATT diode 22 (shown in FIG. 29 for the IMPATTmultiplier module 5), bandpass filter 19, voltage regulator 20 fortransistors and DC bias current regulator 21 for the IMPATT diode. Theheterodyne module 6 is located in a single metal housing with thecoaxial input and waveguide output (waveguide size WR-10). The supplyvoltages come to the transmitter module 6 via feed-through insulators.

The FM signal (at 7.6-7.7 GHz, power of 20 mW) from VCO 4 goes via acoaxial connector to the input of the transistor power amplifier 17(operating at 7.6-7.7 GHz, with gain of +14 dB). Two balanced amplifierstages connected in series operate in the saturation mode. They providemicrowave power of 0.5 W at the output of the power amplifier 17. In onecase, such an amplifier may be realized (as in a preferred embodiment ofthe invention) by utilizing microstrip technology in combination withGaAs field-effect transistors. It is apparent to those skilled in theart, however, that in construction of such amplifier one can apply amonolithic or any other circuit with the same parameters (frequencyrange, gain and power output).

The output signal from the transistor power amplifier 17 is directed tothe silicon multiplying IMPATT diode of the active IMPATT frequencymultiplier 18. Matching between the multiplying IMPATT diode andtransistor amplifier 17 is performed with a microstrip board 26 in amanner similar to that for the transmitter IMPATT multiplier module 5.This IMPATT diode is coupled into the waveguide by the T-shapedwaveguide tee 23, similarly as for transmitter module 5. In contrast totransmitter module 5, in the heterodyne module 6, the 11^(th) (ratherthan 10^(th)) input signal harmonic is separated. At the output of theT-shaped waveguide tee 23, there is a waveguide bandpass filter 19 (seeFIG. 28) whose pass band is 83.1-85.2 GHz. It efficiently suppresses theadjacent harmonics, as well as considerably reduces AM noise of theheterodyne module 6 at the frequency of echo-signal reception (by over60 dB). The output signal (at 83.6-84.7 GHz, with power of no less than10 mW) from the heterodyne active IMPATT multiplier module 6 is directedvia the waveguide output to the heterodyne input of the balance mixer 7.

13. Hybrid Integrated Microstrip Radar Transceiver with One Antenna

13.1 General Description of Hybrid Integrated Microstrip Transceiverwith One Antenna

FIG. 31 shows schematically a transceiver (realized and tested) intendedfor operation as a front-end of automotive radar with operatingfrequency in the 76-77 GHz frequency range. The transceiver is ahomodyne circuit with linear frequency modulation; it operates with asingle transmit/receive antenna. In this embodiment, a MM-wave section116 of the transceiver is made (using the hybrid-integrated microstriptechnology) on a high-resistance silicon substrate. A siliconmultiplying IMPATT diode (optimized for the operating frequency of 76-77GHz) is used as an active element in the receiver section of thetransceiver. Application of the hybrid-integrated technology, as well asuse of a silicon substrate and one active element (silicon IMPATT diode)makes it possible to considerably reduce the size and mass of thetransceiver and improve both its service life and reliability. Under theseries production conditions, high reproducibility of operatingparameters is provided, as well as possibility to produce low-costautomotive radars with the required level of specifications.

The transceiver operates in the following manner. The sweep voltage 100goes from a microprocessor unit 114 to a VCO 101 (tuning range of7.6-7.7 GHz, power output of 7-8 mW). A signal from the VCO 101 goes toa directional coupler 102 and is divided therein in two parts. One partof the signal enters the input of an amplifier 103. Another part of thesignal from the directional coupler 102 is directed to a mixer 109. Asignal from an oscillator 108 (stabilized with a dielectric resonator,DRO) is directed to the LO input of the mixer 109. In the mixer 109, thesignals from the VCO 101 and DRO 108 are converted into the IF signal ofthe mixer 109. The IF signal is provided to the microprocessor unit 114where a digital phase-locked-loop frequency control system is included.It provides high linearity of the VCO 101 frequency tuning and improvesthe VCO 101 spectral characteristics.

After amplification by the oscillator 103, the signal comes to theactive frequency multiplier 104 with high multiplication factor. TheIMPATT diode bias current feeds the input 110 of the frequencymultiplier 104. The 10^(th) harmonic of the signal coming from theamplifier 103 is separated in the multiplier 104 by means ofmatching-transforming circuits (MTC). The frequency of the output signalof the multiplier 104 varies in the 76-77 GHz range; the power output isabout 15 mW. The signal converted in the multiplier 104 is provided to adirectional coupler 105 and is divided therein into two portions. Oneportion of the signal via a microstrip circulator 106 feeds an antenna107 and is radiated into space. A signal reflected from an object isreceived by the same antenna 107 and is directed (via the circulator106) to a mixer 111. The required isolation level is provided in thecirculator 106. Another portion of the signal from the directionalcoupler 105 enters the LO input of the mixer 111. The hybrid-integratedmixer 111 is a balanced circuit. This provides suppression of the LOnoise. At the mixer output 112, the IF signal of the mixer 111(proportional to the difference between the radiated signal and thatreflected from an object) is extracted. This signal is amplified by alow-noise amplifier 113 and is provided to the microprocessor unit 114for processing and obtaining a signal that is proportional to thevelocity and distance to the object. Then, the signal is displayed on anindicator 115.

13.2 Block-Diagram of the Hybrid Integrated Microstrip Active FrequencyMultiplier

The schematic of the hybrid-integrated frequency multiplier 104implemented in accordance with this preferred embodiment of theinvention is shown in FIG. 32. The hybrid integrated-microstripfrequency multiplier 104 includes a decoupling capacitor 119, MTCs 121,123 and 125, microstrip lines 118, 120 and 122 and a silicon multiplyingIMPATT diode chip 126 which is similar to the multiplying IMPATT diodechip 30 shown in FIG. 30 for the hybrid integrated-waveguide embodiment.The signal of low (7.6-7.7 GHz) frequency is provided to the multiplyingIMPATT diode chip 126 via the decoupling capacitor 119, microstrip line120, MTC 121 and MTC 125. The 10^(th) harmonic signal at 76-77 GHz isextracted with the MTC 125 and is provided via the microstrip line 122to the output 127 of the frequency multiplier 104. The IMPATT diode chip126 is supplied with a DC bias current via the MTC 123.

13.3 Layout of the Mm-Wave Section of the Hybrid Integrated MicrostripTransceiver

The MM-wave section of the transceiver is shown enclosed by a dashedline box 116 in FIG. 31. This section 116 size is 10.5×3.8 mm; it ismade on the high-resistance substrates whose thickness is no more than120 μm.

The substrates are made of high-resistance (resistivity no less than 10³Ohm×cm) silicon. On standardized silicon wafers membranes of requiredthickness (no more than 120 μm) are formed. They serve for formation ofpassive components of microwave IC chips using the standardmicroelectronic techniques.

The layout of the transceiver MM-wave section 116 is shown in FIG. 33.The low-frequency (7.6-7.7 GHz) signal enters the input 117. Themultiplying diode DC bias current feeds the input 110. The MTC 123excludes the effect of the IMPATT diode bias current circuitry onpropagation of the low-frequency signals via the microstrip line 120.The MTC 123 is a stub microstrip band-rejection filter designed for thefrequency of 7.6-7.7 GHz.

The MTC 121 gates low-frequency signals and rejects the multiplyingdiode 10^(th) harmonic signal. The MTC 121 is a stub microstripband-rejection filter designed for the frequency 76-77 GHz. The MTC 125transforms the impedance of the IMPATT diode chip 126 in the 76-77 GHzfrequency range. The MTC 125 comprises construction elements of aminiature diode package, i.e., a dielectric bush and a gold many-petallead. The gold many-petal lead (or multi-petal lead) forms thetransformer inductance, while the dielectric bush forms its capacitance.Similar to the multiplying IMPATT diode chip 30 shown in FIG. 30, themultiplying IMPATT diode chip 126 comprises a silicon reverse p⁺-n-n⁺mesa and a gold-plated copper heat sink base. The diode chip 126parameters are optimized in the 76-77 GHz frequency range. The MTC 125resonance frequency lies in the 76-77 GHz range.

The stub microstrip directional coupler 105 sends part of the signal tothe circulator 106 and another part to the LO input of the mixer 111.The mixer 11 is a balanced circuit employing beam-lead GaAs diodes 128.It provides the conversion coefficient better than 10 dB. The arm 129 ofthe circulator 106 is connected to the microstrip antenna 107.

14. Vehicular Implementation

In light of the foregoing, an automotive vehicle including the systemdescribed above would include a radar transceiver including a transmitantenna, a receive antenna separate and isolated from the transmitantenna, a frequency generator for generating a voltage pulse, avoltage-controlled oscillator (VCO) arranged to receive the voltagepulse from the frequency generator and generate a signal, a transmitteractive IMPATT multiplier module arranged to receive the signal from theVCO and generate a radar probing signal which is directed to thetransmit antenna, a heterodyne active IMPATT multiplier module arrangedto receive the signal from the VCO, a first balance mixer arranged toreceive the signal from the VCO, a second balance mixer arranged toreceive a signal from the receive antenna and the heterodyne activeIMPATT multiplier module and derive a first intermediate frequency (IF)signal, a first amplifier for amplifying the output of the secondbalance mixer and providing the amplifier output to the first balancemixer, and a second amplifier for amplifying the output of the firstbalance mixer.

A digital signal processor is coupled to the second amplifier andreceives the output therefrom and generates a control signal forcontrolling a component in the vehicle based on the output from thesecond amplifier. For example, the component may be an adjustablecollision avoidance device in which case, the processor might determinea distance between an object and the vehicle and control the collisionavoidance based on the determined distance. A decreasing distancebetween the object and the vehicle would be indicative of a pendingcollision. The collision avoidance device might cause the steering wheelto be turned to avoid the accident, the brakes to be applied to avoidthe accident.

FIG. 34 is a schematic of a vehicle 50 showing a collision avoidancesystem in accordance with the invention. Vehicle 50 includes severalradar transceivers 52, possibly one on each side of the vehicle 50 asshown, and all of which are coupled to a processor 54. Processor 54 isalso coupled to adjustable components in the vehicle such as brakes 56associated with each tire of the vehicle 50 and a steering system 58connected to the steering wheel, steering shaft and/or steering axle ofthe vehicle 50. Processor 54 includes a collision avoidance programwhich obtains input from the transceivers 52 and based thereon, providesoutput to the brakes 56 and/or steering system 58 as needed. Processor54 can also be coupled to a location determining system 60 whichdetermines the location of the vehicle and a map database 62 whichcorrelates the position of the vehicle 50 to a road on which the vehicle50 is traveling.

In operation to avoid collisions, when data derived from the signalsfrom transceivers 52 is received and is indicative of the possibility ofa collision as determined by processor 54, preferably in considerationof the location of the vehicle 50 as determined by the locationdetermining system 60 and the road on which the vehicle 50 is travelingas provided by the map database 62, processor 54 determines anappropriate manner to adjust the travel of the vehicle 50. Adjustment ofthe travel of the vehicle 50 may entail applying brakes 52 to slow thevehicle or otherwise changing the speed of travel of the vehicle(accelerating), changing the direction of travel of the vehicle viacontrol of the steering system 58 or a combination thereof.

Instead of or in addition to a collision avoidance device, the processor54 could control one or more occupant protection devices (represented byairbag systems 64 in FIG. 34) to deploy the same or prepare the same fordeployment in the event of a collision. Thus, transceivers 52, incombination with processor 54, could be used as an anticipatory sensorsystem which readies one or more airbag systems 64 for deployment andmay actually deploy them prior to an impact involving the vehicle.

Another vehicular application for transceivers in accordance with theinvention would be blind spot monitoring. As shown in FIG. 35, a vehicle66 frequently if not always is driven in such a manner to cause thepresence of blind spots, spots not in the viewing range of the drivereither directly or through the use of mirrors. One such blind spot isdefined by boundary lines 68. To alert the driver to the presence of,for example, another vehicle in the blind spot, a system in accordancewith the invention includes one or more transceivers 70 arranged on thevehicle and in a position to direct radar waves into the blind spot andreceive reflected radar waves from any objects in the blind spot.

Each transceiver 70 is connected to a common processor 72 which in turnis connected to one or more reactive systems 74 in the vehicle 66. Areactive system 74 is one which will alert the driver, e.g., audibly,visually or both in combination, to the presence of another vehicle inthe blind spot if the driver takes action to move his vehicle into thepath of the other vehicle in the blind spot (to prevent a collision).The reactive system 74 could also be a display visible to the driver, inwhich the contents of the blind spot are displayed to the driver toenable him or her to make a decision about moving the vehicle.

Processor 72 can be programmed to apply pattern recognition techniquesto identify the objects in the blind spot. Processor 72 can also bedesigned to correlate with a database 76 of road structures to avoidalerting the driver to objects which are properly in the blind spot aswell as to factor in the path of the road on which the vehicle istraveling when defining the blind spot of the vehicle.

Other vehicular applications in which transceivers described above maybe used include automatic cruise control and precise positioning system.

15. Summary

Disclosed above are methods and apparatus for preventing vehicleaccidents. To this end, a vehicle is equipped with a differential GPS(DGPS) navigational system as well as an inertial navigation subsystem.Part of the system can be an array of infrastructure stations thatpermit the vehicle to exactly determine its position at various pointsalong its path. Such stations would typically be located at intervalssuch as every 50 miles along the roadway, or more or less frequentlydepending on requirements as described below. These stations permit thevehicle to become its own DGPS station and thus to correct for the GPSerrors and to set the position of the vehicle-based initial guidancesystem. It also provides sufficient information for the vehicle to usethe carrier frequency to determine its absolute position to within a fewcentimeters or better for as long as satellite locks are maintaineddepending on the system accuracy. Data is also available to the vehiclethat provides information as to the edges of the roadway, and edges ofthe lanes of the roadway, at the location of the vehicle so that thevehicle control system can continuously determine its location relativeto the roadway edges and/or lane edges. In the initial implementation,the operator operates his or her vehicle and is unaware of the presenceof the accident avoidance system. If, however, the operator falls asleepor for some other reason attempts to drive off the roadway at highspeed, the system will detect that the vehicle is approaching an edge ofthe roadway and will either sound an alarm or prevent the vehicle fromleaving the roadway when doing so would lead to an accident. In somecases, the system will automatically reduce the speed of the vehicle andstop it on the shoulder of the roadway.

It is important to note that the invention as described in the aboveparagraph is in itself a significant improvement to automotive safety.Approximately half of all fatal accidents involve only a single vehiclethat typically leaves the roadway and impacts with a roadside obstacle,cross a yellow line or run a red light or stop sign. This typicallyhappens when the driver in under the influence of alcohol or drugs, hasa medical emergency or simply falls asleep. If this cause of accidentscould be eliminated, the potential exists for saving many thousands ofdeaths per year when all vehicles are equipped with the system of thisinvention. This would make this the single greatest advance inautomotive safety surpassing both seatbelts and airbags in lifesavingpotential.

A first improvement to this embodiment of the invention is to providethe vehicle with a means using radar, laser radar, optical or infraredimaging, or a similar technology, to determine the presence, locationand velocity of other vehicles on the roadway that are not equipped withthe accident avoidance system. The accident avoidance system (RtZF®) ofthis invention will not be able to avoid all accidents with suchvehicles for the reasons discussed above, but will be able to provide alevel of protection which is believed to surpass all known prior artsystems. Some improvement over prior art systems will result from thefact that the equipped vehicle knows the location of the roadway edges,as well as the lane boundaries, not only at the location of the equippedvehicle but also at the location of the other nearby vehicles. Thus, theequipped vehicle will be able to determine that an adjacent vehicle hasalready left its corridor and warn the driver or initiate evasiveaction. In prior art systems, the location of the roadway is not knownleading to significantly less discrimination ability.

A second improvement is to provide communication ability to other nearbysimilarly equipped vehicles permitting the continuous transmission andreception of the locations of all equipped vehicles in the vicinity.With each vehicle knowing the location, and thus the velocity, of allpotential impacting vehicles which are equipped with the RtZF®,collisions between vehicles can be reduced and eventually nearlyeliminated when all vehicles are equipped with the RtZF®. One suchcommunication system involves the use of spread spectrum carrier lesscommunication channels that make efficient use of the availablebandwidth and permit the simultaneous communication of many vehicles.

A third improvement comprises the addition of software to the systemthat permits vehicles on specially designated vehicle corridors for theoperator to relinquish control of the vehicle to the vehicle-basedsystem, and perhaps to a roadway computer system. This then permitsvehicles to travel at high speeds in a close packed formation therebysubstantially increasing the flow rate of vehicles on a given roadway.In order to enter the designated corridors, a vehicle would be requiredto be equipped with the RtZF® system. Similarly, this then provides anincentive to vehicle owners to have their vehicles so equipped so thatthey can enter the controlled corridors and thereby shorten their traveltime. Close packed or platooning travel is facilitated in the inventionand thus supportive of the drag reduction advantages of such travel.But, such travel, although it can be automatically achieved throughimplementation of the proper algorithms in a very simple manner, is notrequired.

Prior art systems require expensive modifications to highways to permitsuch controlled high speed close packed travel. Such modifications alsorequire a substantial infrastructure to support the system. The RtZF® ofthe present invention, in its simplest form, does not require anymodification to the roadway but rather relies primarily on the GPS orsimilar satellite system or other precise locating system. The edge andlane boundary information is either present within the vehicle RtZF®memory or transmitted to the vehicle as it travels along the road. Thepermitted speed of travel is also communicated to the vehicles on therestricted corridor and thus each vehicle travels at the appointedspeed. Since each vehicle knows the location of all other vehicles inthe vicinity, should one vehicle slow down, due to an enginemalfunction, for example, appropriate action can be taken to avoid anaccident. Vehicles do not need to travel in groups as suggested andrequired by some prior art systems. Rather, each vehicle mayindependently enter the corridor and travel at the system defined speeduntil it leaves, which may entail notifying the system of a destination.

Another improvement involves the transmission of additional dataconcerning weather conditions, road conditions traffic accidents etc. tothe equipped vehicle so that the speed of that vehicle can be limited toa safe speed depending on road conditions, for example. If moisture ispresent on the roadway and the temperature is dropping to the point thatice might be building up on the road surface, the vehicle can benotified by the roadway information system and prevented from travelingat an unsafe speed.

In contrast to some prior art systems, with the RtZF® system inaccordance with the invention, especially when all vehicles areappropriately equipped, automatic braking of the vehicle should rarelybe necessary and steering and throttle control should in most cases besufficient to prevent accidents. In most cases, braking means theaccident wasn't anticipated.

It is important to understand that this is a process control problem.The process is designed so that it should not fail and thus allaccidents should be eliminated. Events that are troublesome to thesystem include a deer running in front of the vehicle, a box falling offof a truck, a rock rolling onto the roadway and a catastrophic failureof a vehicle. Continuous improvement to the process is thus requiredbefore these events are substantially eliminated. Each vehicle,individual driver and vehicle control system is part of the system andupon observing that such an event has occurred, he or she should havethe option of stopping the process to prevent or mitigate an emergency.All equipped vehicles therefore have the capability of communicatingthat the process is stopped and therefore that the vehicle speed, forexample, should be substantially reduced until the vehicle has passedthe troubled spot or until the problem ceases to exist. In other words,each vehicle and each driver is part of the process. In one manner, eachvehicle is a probe vehicle.

The RtZF® system in accordance with the invention will thus start simpleby reducing single vehicle accidents and evolve. The system has thecapability to solve the entire problem by eliminating automobileaccidents.

Furthermore, disclosed above are methods and apparatus for eliminatingaccidents by accurately determining the position of a vehicle,accurately knowing the position of the road and communicating betweenvehicles and between the vehicle and the infrastructure supportingtravel. People get into accidents when they go too fast for theconditions and when they get out of their corridor. This embodimenteliminates these and other causes of accidents. In multilane highways,this system prevents people from shifting lanes if there are othervehicles in the blind spot, thus, solving the blind spot problem. Thevehicle would always be traveling down a corridor where the width of thecorridor may be a lane or the entire road width or something in betweendepending on road conditions and the presence of other vehicles. Thisembodiment is implemented through the use of both an inertial navigationsystem (INS or IMU) and a DGPS, in some cases with carrier frequencyenhancement. Due to the fact that the signals from at least four GPS orGLONASS satellites are not always available and to errors caused bymultiple path reception from a given satellite, the DGPS systems cannotbe totally relied upon. Therefore the INS is a critical part of thesystem. This will improve as more satellites are launched and additionalground stations are added. It will also significantly improve when theWAAS and LAAS systems are implemented and refined to work with landvehicles as well as airplanes. It will also be improved with theimplementation of PPS.

Also disclosed above is an arrangement for transferring informationbetween a vehicle and one or more transmitters separate from the vehiclewhich generally comprises an antenna mounted on the vehicle and capableof receiving radio frequency waves emitted by the transmitter andcontaining information, a position determining device for determiningthe position of the vehicle, and a processor coupled to the antenna andthe position determining device and arranged to analyze the wavesreceived by the antenna, determine whether any received waves containinformation of interest for operation of the vehicle based on thevehicle's position as determined by the position determining device, andextract the information of interest only from the received wavesdetermined to contain information of interest. The information ofinterest may be information about the transmitter such as its location,speed, velocity, etc., or information relating to road conditions,weather and the like.

Each transmitter can transmit radio frequency waves containingpositional information about the transmitter, information necessitatedby the information transferring arrangement and additional informationof potential interest for operation of the vehicle. In this case, theprocessor is arranged to extract only the positional information and theinformation necessitated by the information transferring arrangementfrom all received waves and additional information only from receivedwaves determined to contain information of interest for operation of thevehicle. The information of interest may be a distance between thetransmitter and the vehicle, an angle between the transmitter and thevehicle, a direction between the transmitter and the vehicle, a place ofthe transmitter and a geographic position of the transmitter andcombinations thereof. The processor can analyze the positionalinformation extracted from all of the received waves to determinewhether any received waves originate from a transmitter within apre-determined area relative to the vehicle whereby received waves fromany transmitter determined to be within the pre-determined area relativeto the vehicle are considered to contain information of interest foroperation of the vehicle.

In some embodiments, the processor directs the transmission of encodedsignals from the antenna including information about the position of thevehicle. The processor may derive the encoded signals using a code basedon the position of the vehicle.

The processor can direct the transmission of encoded signals from theantenna including information about the position of the vehicle andidentification of the vehicle. Also, the processor can direct thetransmission of a unique pseudorandom noise signal from the antennacomposed of frequencies within a pre-selected band.

Optionally, a speed determining device is arranged in the vehicle fordetermining the speed of the vehicle in which case, the processor iscoupled to the speed determining device and encodes signals includinginformation about the speed of the vehicle. In a similar manner, amotion determining device may be arranged in the vehicle for determiningthe direction of motion of the vehicle, in which case, the processor iscoupled to the motion determining device and encodes signals includinginformation about the direction of motion of the vehicle.

In a non-limiting embodiment, the processor derives encoded signals byphase modulation of distance or time between code transmissions, phaseor amplitude modulation of the code sequences, changes of the polarityof the entire code sequence or the individual code segments, orbandwidth modulation of the code sequence. The encoded signals can bederived using a code based on the position of the vehicle.

The processor can direct the transmission of a unique pseudorandom noisesignal from the antenna in a carrier-less fashion composed offrequencies within a pre-selected band.

In a method for transferring information between a vehicle and one ormore transmitters separate from the vehicle in accordance with theinvention, each transmitter transmits radio frequency waves containingpositional information about the transmitter, information necessitatedby the information transferring method and additional information ofpotential interest for operation of the vehicle. An antenna is arrangedon the vehicle capable of receiving the radio frequency waves emitted bythe transmitter. The position of the vehicle is determined. Wavestransmitted by each transmitter are received via the antenna. The wavesreceived by the antenna are analyzed to extract the positionalinformation about the transmitter and information necessitated by theinformation transferring method from each wave. From the extractedpositional information, a determination is made as to whether anytransmitted waves contain additional information of actual interest foroperation of the vehicle. If so, the additional information is extractedonly from those transmitted signals determined to contain information ofactual interest for operation of the vehicle.

The additional information contained in each transmitted wave may be adistance between the transmitter and the vehicle, an angle between thetransmitter and the vehicle, a direction between the transmitter and thevehicle, a place of the transmitter and a geographic position of thetransmitter and combinations thereof.

The wave analysis step may entail analyzing the received waves todetermine whether any received waves originate from a transmitter withina pre-determined area relative to the vehicle, the informationextracting step comprising extracting additional information only fromthe waves received from any transmitter determined to be within thepre-determined area relative to the vehicle. Optionally, a directionbetween each transmitter within the pre-determined area relative to thevehicle and the vehicle is determined and the extraction of additionalinformation from waves received from the transmitters within thepre-determined area relative to the vehicle limited to only those whosedirection to the vehicle affects the traveling of the vehicle. Inaddition to or instead of the foregoing, the direction of travel of eachtransmitter (vehicle when vehicle-mounted) within the pre-determinedarea relative to the vehicle and the vehicle is determined and theextraction of additional information from waves received from thetransmitters within the pre-determined area relative to the vehiclelimited to only those whose direction of travel affects the traveling ofthe vehicle.

Another wave analysis may involve determining whether any received wavesoriginate from a transmitter traveling in a direction toward thevehicle's current position and/or the vehicle's projected position basedon the vehicle's current position and direction of travel, in whichcase, additional information may be extracted only from the wavesreceived from any transmitter traveling toward the vehicle's currentand/or projected position.

Another alternative or additional form of wave analysis may involvedetermining whether any of the signals originate from transmittersdedicated to the transmission of road conditions or traffic data wherebythe signals containing information of interest originate from thetransmitters dedicated to the transmission of road conditions or trafficdata.

Encoded signals may be transmitted from the antenna includinginformation about the position of the vehicle. A code to use forencoding the signal may be determined based on the position of thevehicle.

A method for transferring information from transmitters to a movingvehicle in accordance with the invention includes determining theposition of the vehicle, transmitting a signal from each transmittercontaining its position, information necessitated by the informationtransferring method and additional information, arranging an antenna onthe vehicle, receiving the signals from the transmitters via theantenna, analyzing the signals received by the antenna to extract thepositional information about the transmitters and informationnecessitated by the information transferring method from each signal,determining whether any transmitters are situated within apre-determined area relative to the vehicle, and extracting theadditional information only from signals received from transmitterswithin the pre-determined area relative to the vehicle.

The location of the transmitters may be on other vehicles, but may alsobe on other stationary or moving objects. The position of eachtransmitter can be determined using a GPS-based system.

The information of interest may include a distance between thetransmitter and the vehicle, an angle between the transmitter and thevehicle, a direction between the transmitter and the vehicle, a place ofthe transmitter and a geographic position of the transmitter andcombinations thereof.

Optionally, a direction between each transmitter within thepre-determined area relative to the vehicle and the vehicle may bedetermined and the extraction of additional information from wavesreceived from the transmitters within the pre-determined area relativeto the vehicle limited to only those whose direction to the vehicleaffects the traveling of the vehicle. In addition to or instead of theforegoing, the direction of travel of each transmitter (vehicle whenvehicle-mounted) within the pre-determined area relative to the vehicleand the vehicle is determined and the extraction of additionalinformation from waves received from the transmitters within thepre-determined area relative to the vehicle limited to only those whosedirection of travel affects the traveling of the vehicle.

Another wave analysis may involve determining whether any received wavesoriginate from a transmitter traveling in a direction toward thevehicle's current position and/or the vehicle's projected position basedon the vehicle's current position and direction of travel, in whichcase, additional information may be extracted only from the wavesreceived from any transmitter traveling toward the vehicle's currentand/or projected position. Encoded signals may be transmitted from theantenna including information about the position of the vehicle. A codeto use for encoding the signal may be determined based on the positionof the vehicle.

A method for avoiding collisions between moving vehicles in accordancewith the invention comprises determining the position of each vehicle,equipping each vehicle with a transmitter/receiver, transmitting asignal from each transmitter/receiver containing its position andadditional information, receiving the signals at eachtransmitter/receiver from the other transmitter/receivers, and analyzingthe signals at each transmitter/receiver to extract the positionalinformation about the vehicles equipped with the othertransmitter/receivers from each signal in order to determine whether anyvehicles are situated within a pre-determined area relative to thattransmitter/receiver. If so, the additional information is extractedonly from signals received from other transmitter/receivers in thevehicles within the pre-determined area relative to thattransmitter/receiver and the additional information is analyzed toascertain whether a collision with the vehicles equipped with the othertransmitter/receivers is likely to occur in order to enable evasiveaction to be taken to prevent the collision.

Optionally, a direction between each of the vehicle equipped with theother transmitter/receivers within the pre-determined distance from thattransmitter/receiver is determined and the extraction of the additionalinformation limited only those whose direction affects the traveling ofthe vehicle. The signals transmitted by each transmitter/receivers canbe encoded by means of a code selected based on the position of eachtransmitter/receiver, which may be determined using a GPS-based system.

A method for transferring information between a vehicle and one or moretransmitters separate from the vehicle in accordance with the inventioncomprises mounting an antenna on the vehicle which is capable ofreceiving radio frequency waves emitted by the transmitter containinginformation, determining the position of the vehicle, analyzing thewaves received by the antenna, determining whether any received wavescontain information of interest for operation of the vehicle based onthe vehicle's position and extracting the information of interest onlyfrom the received waves determined to contain information of interest.

While the invention has been illustrated and described in detail in thedrawings and the foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly preferred embodiments have been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

This application is one in a series of applications covering safety andother systems for vehicles and other uses. The disclosure herein goesbeyond that needed to support the claims of the particular inventionthat is claimed herein. This is not to be construed that the inventorsare thereby releasing the unclaimed disclosure and subject matter intothe public domain. Rather, it is intended that patent applications havebeen or will be filed to cover all of the subject matter disclosedabove.

1. A system for determining accurate position of an object, comprising:a GPS positioning system arranged to communicate with one or moresatellites to obtain GPS signals therefrom; a correction unit coupled tosaid positioning system and arranged to receive or derive positionalcorrections for positional data derived from the GPS signals to therebyimprove accuracy of the position of the object provided by saidpositioning system; and a notification system for notifying a personconcerned with the position of the object about the current position ofthe object.
 2. The system of claim 1, wherein the object is a vehicle.3. The system of claim 1, wherein said correction unit is a DGPS-basedcorrection unit.
 4. The system of claim 1, further comprising anavigation system coupled to said correction unit for receiving andacting upon the accurate positional information of the object providedby said correction unit.
 5. The system of claim 4, wherein the object isa vehicle, further comprising a map database coupled to said navigationsystem, said navigation system being arranged to receive informationabout a travel lane the vehicle is travelling on and guiding an operatorof the vehicle based on the accurate positional information and travellane information.
 6. The system of claim 5, wherein said notificationsystem is a warning system arranged to notify an operator of the vehicleof the position of the vehicle to prevent accidents involving thevehicle.
 7. The system of claim 5, further comprising a display fordisplaying the position of the vehicle on a map along with the positionof other vehicles.
 8. The system of claim 1, wherein said correctionunit is arranged to communicate with satellites to receive positionalcorrections therefrom.
 9. The system of claim 1, wherein said correctionunit is arranged to communicate with ground base stations to receivepositional corrections therefrom.
 10. The system of claim 1, wherein theobject is a vehicle, further comprising means for communicating withother vehicles and transmitting GPS signals and/or positionalcorrections to the other vehicles and/or receiving GPS signals and/orpositional corrections from the other vehicles.
 11. The system of claim10, further comprising a display for displaying the position of thevehicle and other vehicles on a map.
 12. A vehicular system fordetermining accurate position of the vehicle, comprising: a GPSpositioning system arranged to communicate with one or more satellitesto obtain GPS signals therefrom; a correction unit coupled to saidpositioning system and arranged to receive or derive positionalcorrections for positional data derived from the GPS signals to therebyimprove accuracy of the position of the vehicle provided by saidpositioning system; means for communicating with other vehicles andtransmitting GPS signals and/or positional corrections to the othervehicles and/or receiving GPS signals and/or positional corrections fromthe other vehicles; and a display for displaying the position of thevehicle and other vehicles on a map.
 13. The system of claim 12, furthercomprising a notification system for notifying an operator of thevehicle about a possible collision between the vehicle and one of theother vehicles.
 14. The system of claim 12, wherein said correction unitis a DGPS-based correction unit.
 15. The system of claim 12, furthercomprising a navigation system coupled to said correction unit forreceiving and acting upon the accurate positional information of theobject provided by said correction unit.
 16. The system of claim 15,further comprising a map database coupled to said navigation system,said navigation system being arranged to receive information about atravel lane the vehicle is travelling on and guiding an operator of thevehicle based on the accurate positional information and travel laneinformation.
 17. The system of claim 12, wherein said correction unit isarranged to communicate with satellites to receive positionalcorrections therefrom.
 18. The system of claim 12, wherein saidcorrection unit is arranged to communicate with ground base stations toreceive positional corrections therefrom.
 19. A system for determiningaccurate position of an object, comprising: a GPS positioning systemarranged to communicate with one or more satellites to obtain GPSsignals therefrom; a DGPS correction unit coupled to said positioningsystem and arranged to receive or derive positional corrections forpositional data derived from the GPS signals to thereby improve accuracyof the position of the object provided by said positioning system; anavigation system coupled to said correction unit for receiving theaccurate positional information of the object provided by saidcorrection unit and generating data about movement of the object; and anotification system for notifying a person concerned with the positionof the object about the movement of the object.
 20. The system of claim19, wherein the object is a vehicle, further comprising a map databasecoupled to said navigation system, said navigation system being arrangedto receive information about a travel lane the vehicle is traveling onand guiding an operator of the vehicle based on the accurate positionalinformation and travel lane information, said notification system beinga warning system arranged to notify an operator of the vehicle of theposition of the vehicle to prevent accidents involving the vehicle.